text: /*
   * Indeo Video v3 compatible decoder
   * Copyright (c) 2009 - 2011 Maxim Poliakovski
   *
   * This file is part of FFmpeg.
   *
   * FFmpeg is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * FFmpeg is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with FFmpeg; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  /**
   * @file
   * This is a decoder for Intel Indeo Video v3.
   * It is based on vector quantization, run-length coding and motion compensation.
   * Known container formats: .avi and .mov
   * Known FOURCCs: 'IV31', 'IV32'
   *
   * @see http://wiki.multimedia.cx/index.php?title=Indeo_3
   */
  
  #include "libavutil/imgutils.h"
  #include "libavutil/intreadwrite.h"
  #include "avcodec.h"
  #include "dsputil.h"
  #include "bytestream.h"
  #include "get_bits.h"
  #include "internal.h"
  
  #include "indeo3data.h"
  
  /* RLE opcodes. */
  enum {
      RLE_ESC_F9    = 249, ///< same as RLE_ESC_FA + do the same with next block
      RLE_ESC_FA    = 250, ///< INTRA: skip block, INTER: copy data from reference
      RLE_ESC_FB    = 251, ///< apply null delta to N blocks / skip N blocks
      RLE_ESC_FC    = 252, ///< same as RLE_ESC_FD + do the same with next block
      RLE_ESC_FD    = 253, ///< apply null delta to all remaining lines of this block
      RLE_ESC_FE    = 254, ///< apply null delta to all lines up to the 3rd line
      RLE_ESC_FF    = 255  ///< apply null delta to all lines up to the 2nd line
  };
  
  
  /* Some constants for parsing frame bitstream flags. */
  #define BS_8BIT_PEL     (1 << 1) ///< 8bit pixel bitdepth indicator
  #define BS_KEYFRAME     (1 << 2) ///< intra frame indicator
  #define BS_MV_Y_HALF    (1 << 4) ///< vertical mv halfpel resolution indicator
  #define BS_MV_X_HALF    (1 << 5) ///< horizontal mv halfpel resolution indicator
  #define BS_NONREF       (1 << 8) ///< nonref (discardable) frame indicator
  #define BS_BUFFER        9       ///< indicates which of two frame buffers should be used
  
  
  typedef struct Plane {
      uint8_t         *buffers[2];
      uint8_t         *pixels[2]; ///< pointer to the actual pixel data of the buffers above
      uint32_t        width;
      uint32_t        height;
      uint32_t        pitch;
  } Plane;
  
  #define CELL_STACK_MAX  20
  
  typedef struct Cell {
      int16_t         xpos;       ///< cell coordinates in 4x4 blocks
      int16_t         ypos;
      int16_t         width;      ///< cell width  in 4x4 blocks
      int16_t         height;     ///< cell height in 4x4 blocks
      uint8_t         tree;       ///< tree id: 0- MC tree, 1 - VQ tree
      const int8_t    *mv_ptr;    ///< ptr to the motion vector if any
  } Cell;
  
  typedef struct Indeo3DecodeContext {
      AVCodecContext *avctx;
      AVFrame         frame;
      DSPContext      dsp;
  
      GetBitContext   gb;
      int             need_resync;
      int             skip_bits;
      const uint8_t   *next_cell_data;
      const uint8_t   *last_byte;
      const int8_t    *mc_vectors;
      unsigned        num_vectors;    ///< number of motion vectors in mc_vectors
  
      int16_t         width, height;
      uint32_t        frame_num;      ///< current frame number (zero-based)
      uint32_t        data_size;      ///< size of the frame data in bytes
      uint16_t        frame_flags;    ///< frame properties
      uint8_t         cb_offset;      ///< needed for selecting VQ tables
      uint8_t         buf_sel;        ///< active frame buffer: 0 - primary, 1 -secondary
      const uint8_t   *y_data_ptr;
      const uint8_t   *v_data_ptr;
      const uint8_t   *u_data_ptr;
      int32_t         y_data_size;
      int32_t         v_data_size;
      int32_t         u_data_size;
      const uint8_t   *alt_quant;     ///< secondary VQ table set for the modes 1 and 4
      Plane           planes[3];
  } Indeo3DecodeContext;
  
  
  static uint8_t requant_tab[8][128];
  
  /*
   *  Build the static requantization table.
   *  This table is used to remap pixel values according to a specific
   *  quant index and thus avoid overflows while adding deltas.
   */
  static av_cold void build_requant_tab(void)
  {
      static int8_t offsets[8] = { 1, 1, 2, -3, -3, 3, 4, 4 };
      static int8_t deltas [8] = { 0, 1, 0,  4,  4, 1, 0, 1 };
  
      int i, j, step;
  
      for (i = 0; i < 8; i++) {
          step = i + 2;
          for (j = 0; j < 128; j++)
                  requant_tab[i][j] = (j + offsets[i]) / step * step + deltas[i];
      }
  
      /* some last elements calculated above will have values >= 128 */
      /* pixel values shall never exceed 127 so set them to non-overflowing values */
      /* according with the quantization step of the respective section */
      requant_tab[0][127] = 126;
      requant_tab[1][119] = 118;
      requant_tab[1][120] = 118;
      requant_tab[2][126] = 124;
      requant_tab[2][127] = 124;
      requant_tab[6][124] = 120;
      requant_tab[6][125] = 120;
      requant_tab[6][126] = 120;
      requant_tab[6][127] = 120;
  
      /* Patch for compatibility with the Intel's binary decoders */
      requant_tab[1][7] = 10;
      requant_tab[4][8] = 10;
  }
  
  
  static av_cold int allocate_frame_buffers(Indeo3DecodeContext *ctx,
                                            AVCodecContext *avctx, int luma_width, int luma_height)
  {
      int p, chroma_width, chroma_height;
      int luma_pitch, chroma_pitch, luma_size, chroma_size;
  
      if (luma_width  < 16 || luma_width  > 640 ||
          luma_height < 16 || luma_height > 480 ||
          luma_width  &  3 || luma_height &   3) {
          av_log(avctx, AV_LOG_ERROR, "Invalid picture dimensions: %d x %d!\n",
                 luma_width, luma_height);
          return AVERROR_INVALIDDATA;
      }
  
      ctx->width  = luma_width ;
      ctx->height = luma_height;
  
      chroma_width  = FFALIGN(luma_width  >> 2, 4);
      chroma_height = FFALIGN(luma_height >> 2, 4);
  
      luma_pitch   = FFALIGN(luma_width,   16);
      chroma_pitch = FFALIGN(chroma_width, 16);
  
      /* Calculate size of the luminance plane.  */
      /* Add one line more for INTRA prediction. */
      luma_size = luma_pitch * (luma_height + 1);
  
      /* Calculate size of a chrominance planes. */
      /* Add one line more for INTRA prediction. */
      chroma_size = chroma_pitch * (chroma_height + 1);
  
      /* allocate frame buffers */
      for (p = 0; p < 3; p++) {
          ctx->planes[p].pitch  = !p ? luma_pitch  : chroma_pitch;
          ctx->planes[p].width  = !p ? luma_width  : chroma_width;
          ctx->planes[p].height = !p ? luma_height : chroma_height;
  
          ctx->planes[p].buffers[0] = av_malloc(!p ? luma_size : chroma_size);
          ctx->planes[p].buffers[1] = av_malloc(!p ? luma_size : chroma_size);
  
          /* fill the INTRA prediction lines with the middle pixel value = 64 */
          memset(ctx->planes[p].buffers[0], 0x40, ctx->planes[p].pitch);
          memset(ctx->planes[p].buffers[1], 0x40, ctx->planes[p].pitch);
  
          /* set buffer pointers = buf_ptr + pitch and thus skip the INTRA prediction line */
          ctx->planes[p].pixels[0] = ctx->planes[p].buffers[0] + ctx->planes[p].pitch;
          ctx->planes[p].pixels[1] = ctx->planes[p].buffers[1] + ctx->planes[p].pitch;
          memset(ctx->planes[p].pixels[0], 0, ctx->planes[p].pitch * ctx->planes[p].height);
          memset(ctx->planes[p].pixels[1], 0, ctx->planes[p].pitch * ctx->planes[p].height);
      }
  
      return 0;
  }
  
  
  static av_cold void free_frame_buffers(Indeo3DecodeContext *ctx)
  {
      int p;
  
      ctx->width=
      ctx->height= 0;
  
      for (p = 0; p < 3; p++) {
          av_freep(&ctx->planes[p].buffers[0]);
          av_freep(&ctx->planes[p].buffers[1]);
          ctx->planes[p].pixels[0] = ctx->planes[p].pixels[1] = 0;
      }
  }
  
  
  /**
   *  Copy pixels of the cell(x + mv_x, y + mv_y) from the previous frame into
   *  the cell(x, y) in the current frame.
   *
   *  @param ctx      pointer to the decoder context
   *  @param plane    pointer to the plane descriptor
   *  @param cell     pointer to the cell  descriptor
   */
  static void copy_cell(Indeo3DecodeContext *ctx, Plane *plane, Cell *cell)
  {
      int     h, w, mv_x, mv_y, offset, offset_dst;
      uint8_t *src, *dst;
  
      /* setup output and reference pointers */
      offset_dst  = (cell->ypos << 2) * plane->pitch + (cell->xpos << 2);
      dst         = plane->pixels[ctx->buf_sel] + offset_dst;
      if(cell->mv_ptr){
      mv_y        = cell->mv_ptr[0];
      mv_x        = cell->mv_ptr[1];
      }else
          mv_x= mv_y= 0;
      offset      = offset_dst + mv_y * plane->pitch + mv_x;
      src         = plane->pixels[ctx->buf_sel ^ 1] + offset;
  
      h = cell->height << 2;
  
      for (w = cell->width; w > 0;) {
          /* copy using 16xH blocks */
          if (!((cell->xpos << 2) & 15) && w >= 4) {
              for (; w >= 4; src += 16, dst += 16, w -= 4)
                  ctx->dsp.put_no_rnd_pixels_tab[0][0](dst, src, plane->pitch, h);
          }
  
          /* copy using 8xH blocks */
          if (!((cell->xpos << 2) & 7) && w >= 2) {
              ctx->dsp.put_no_rnd_pixels_tab[1][0](dst, src, plane->pitch, h);
              w -= 2;
              src += 8;
              dst += 8;
          }
  
          if (w >= 1) {
              copy_block4(dst, src, plane->pitch, plane->pitch, h);
              w--;
              src += 4;
              dst += 4;
          }
      }
  }
  
  
  /* Average 4/8 pixels at once without rounding using SWAR */
  #define AVG_32(dst, src, ref) \
      AV_WN32A(dst, ((AV_RN32A(src) + AV_RN32A(ref)) >> 1) & 0x7F7F7F7FUL)
  
  #define AVG_64(dst, src, ref) \
      AV_WN64A(dst, ((AV_RN64A(src) + AV_RN64A(ref)) >> 1) & 0x7F7F7F7F7F7F7F7FULL)
  
  
  /*
   *  Replicate each even pixel as follows:
   *  ABCDEFGH -> AACCEEGG
   */
  static inline uint64_t replicate64(uint64_t a) {
  #if HAVE_BIGENDIAN
      a &= 0xFF00FF00FF00FF00ULL;
      a |= a >> 8;
  #else
      a &= 0x00FF00FF00FF00FFULL;
      a |= a << 8;
  #endif
      return a;
  }
  
  static inline uint32_t replicate32(uint32_t a) {
  #if HAVE_BIGENDIAN
      a &= 0xFF00FF00UL;
      a |= a >> 8;
  #else
      a &= 0x00FF00FFUL;
      a |= a << 8;
  #endif
      return a;
  }
  
  
  /* Fill n lines with 64bit pixel value pix */
  static inline void fill_64(uint8_t *dst, const uint64_t pix, int32_t n,
                             int32_t row_offset)
  {
      for (; n > 0; dst += row_offset, n--)
          AV_WN64A(dst, pix);
  }
  
  
  /* Error codes for cell decoding. */
  enum {
      IV3_NOERR       = 0,
      IV3_BAD_RLE     = 1,
      IV3_BAD_DATA    = 2,
      IV3_BAD_COUNTER = 3,
      IV3_UNSUPPORTED = 4,
      IV3_OUT_OF_DATA = 5
  };
  
  
  #define BUFFER_PRECHECK \
  if (*data_ptr >= last_ptr) \
      return IV3_OUT_OF_DATA; \
  
  #define RLE_BLOCK_COPY \
      if (cell->mv_ptr || !skip_flag) \
          copy_block4(dst, ref, row_offset, row_offset, 4 << v_zoom)
  
  #define RLE_BLOCK_COPY_8 \
      pix64 = AV_RN64A(ref);\
      if (is_first_row) {/* special prediction case: top line of a cell */\
          pix64 = replicate64(pix64);\
          fill_64(dst + row_offset, pix64, 7, row_offset);\
          AVG_64(dst, ref, dst + row_offset);\
      } else \
          fill_64(dst, pix64, 8, row_offset)
  
  #define RLE_LINES_COPY \
      copy_block4(dst, ref, row_offset, row_offset, num_lines << v_zoom)
  
  #define RLE_LINES_COPY_M10 \
      pix64 = AV_RN64A(ref);\
      if (is_top_of_cell) {\
          pix64 = replicate64(pix64);\
          fill_64(dst + row_offset, pix64, (num_lines << 1) - 1, row_offset);\
          AVG_64(dst, ref, dst + row_offset);\
      } else \
          fill_64(dst, pix64, num_lines << 1, row_offset)
  
  #define APPLY_DELTA_4 \
      AV_WN16A(dst + line_offset    ,\
               (AV_RN16A(ref    ) + delta_tab->deltas[dyad1]) & 0x7F7F);\
      AV_WN16A(dst + line_offset + 2,\
               (AV_RN16A(ref + 2) + delta_tab->deltas[dyad2]) & 0x7F7F);\
      if (mode >= 3) {\
          if (is_top_of_cell && !cell->ypos) {\
              AV_COPY32(dst, dst + row_offset);\
          } else {\
              AVG_32(dst, ref, dst + row_offset);\
          }\
      }
  
  #define APPLY_DELTA_8 \
      /* apply two 32-bit VQ deltas to next even line */\
      if (is_top_of_cell) { \
          AV_WN32A(dst + row_offset    , \
                   (replicate32(AV_RN32A(ref    )) + delta_tab->deltas_m10[dyad1]) & 0x7F7F7F7F);\
          AV_WN32A(dst + row_offset + 4, \
                   (replicate32(AV_RN32A(ref + 4)) + delta_tab->deltas_m10[dyad2]) & 0x7F7F7F7F);\
      } else { \
          AV_WN32A(dst + row_offset    , \
                   (AV_RN32A(ref    ) + delta_tab->deltas_m10[dyad1]) & 0x7F7F7F7F);\
          AV_WN32A(dst + row_offset + 4, \
                   (AV_RN32A(ref + 4) + delta_tab->deltas_m10[dyad2]) & 0x7F7F7F7F);\
      } \
      /* odd lines are not coded but rather interpolated/replicated */\
      /* first line of the cell on the top of image? - replicate */\
      /* otherwise - interpolate */\
      if (is_top_of_cell && !cell->ypos) {\
          AV_COPY64(dst, dst + row_offset);\
      } else \
          AVG_64(dst, ref, dst + row_offset);
  
  
  #define APPLY_DELTA_1011_INTER \
      if (mode == 10) { \
          AV_WN32A(dst                 , \
                   (AV_RN32A(dst                 ) + delta_tab->deltas_m10[dyad1]) & 0x7F7F7F7F);\
          AV_WN32A(dst + 4             , \
                   (AV_RN32A(dst + 4             ) + delta_tab->deltas_m10[dyad2]) & 0x7F7F7F7F);\
          AV_WN32A(dst + row_offset    , \
                   (AV_RN32A(dst + row_offset    ) + delta_tab->deltas_m10[dyad1]) & 0x7F7F7F7F);\
          AV_WN32A(dst + row_offset + 4, \
                   (AV_RN32A(dst + row_offset + 4) + delta_tab->deltas_m10[dyad2]) & 0x7F7F7F7F);\
      } else { \
          AV_WN16A(dst                 , \
                   (AV_RN16A(dst                 ) + delta_tab->deltas[dyad1]) & 0x7F7F);\
          AV_WN16A(dst + 2             , \
                   (AV_RN16A(dst + 2             ) + delta_tab->deltas[dyad2]) & 0x7F7F);\
          AV_WN16A(dst + row_offset    , \
                   (AV_RN16A(dst + row_offset    ) + delta_tab->deltas[dyad1]) & 0x7F7F);\
          AV_WN16A(dst + row_offset + 2, \
                   (AV_RN16A(dst + row_offset + 2) + delta_tab->deltas[dyad2]) & 0x7F7F);\
      }
  
  
  static int decode_cell_data(Cell *cell, uint8_t *block, uint8_t *ref_block,
                              int pitch, int h_zoom, int v_zoom, int mode,
                              const vqEntry *delta[2], int swap_quads[2],
                              const uint8_t **data_ptr, const uint8_t *last_ptr)
  {
      int           x, y, line, num_lines;
      int           rle_blocks = 0;
      uint8_t       code, *dst, *ref;
      const vqEntry *delta_tab;
      unsigned int  dyad1, dyad2;
      uint64_t      pix64;
      int           skip_flag = 0, is_top_of_cell, is_first_row = 1;
      int           row_offset, blk_row_offset, line_offset;
  
      row_offset     =  pitch;
      blk_row_offset = (row_offset << (2 + v_zoom)) - (cell->width << 2);
      line_offset    = v_zoom ? row_offset : 0;
  
      if (cell->height & v_zoom || cell->width & h_zoom)
          return IV3_BAD_DATA;
  
      for (y = 0; y < cell->height; is_first_row = 0, y += 1 + v_zoom) {
          for (x = 0; x < cell->width; x += 1 + h_zoom) {
              ref = ref_block;
              dst = block;
  
              if (rle_blocks > 0) {
                  if (mode <= 4) {
                      RLE_BLOCK_COPY;
                  } else if (mode == 10 && !cell->mv_ptr) {
                      RLE_BLOCK_COPY_8;
                  }
                  rle_blocks--;
              } else {
                  for (line = 0; line < 4;) {
                      num_lines = 1;
                      is_top_of_cell = is_first_row && !line;
  
                      /* select primary VQ table for odd, secondary for even lines */
                      if (mode <= 4)
                          delta_tab = delta[line & 1];
                      else
                          delta_tab = delta[1];
                      BUFFER_PRECHECK;
                      code = bytestream_get_byte(data_ptr);
                      if (code < 248) {
                          if (code < delta_tab->num_dyads) {
                              BUFFER_PRECHECK;
                              dyad1 = bytestream_get_byte(data_ptr);
                              dyad2 = code;
                              if (dyad1 >= delta_tab->num_dyads || dyad1 >= 248)
                                  return IV3_BAD_DATA;
                          } else {
                              /* process QUADS */
                              code -= delta_tab->num_dyads;
                              dyad1 = code / delta_tab->quad_exp;
                              dyad2 = code % delta_tab->quad_exp;
                              if (swap_quads[line & 1])
                                  FFSWAP(unsigned int, dyad1, dyad2);
                          }
                          if (mode <= 4) {
                              APPLY_DELTA_4;
                          } else if (mode == 10 && !cell->mv_ptr) {
                              APPLY_DELTA_8;
                          } else {
                              APPLY_DELTA_1011_INTER;
                          }
                      } else {
                          /* process RLE codes */
                          switch (code) {
                          case RLE_ESC_FC:
                              skip_flag  = 0;
                              rle_blocks = 1;
                              code       = 253;
                              /* FALLTHROUGH */
                          case RLE_ESC_FF:
                          case RLE_ESC_FE:
                          case RLE_ESC_FD:
                              num_lines = 257 - code - line;
                              if (num_lines <= 0)
                                  return IV3_BAD_RLE;
                              if (mode <= 4) {
                                  RLE_LINES_COPY;
                              } else if (mode == 10 && !cell->mv_ptr) {
                                  RLE_LINES_COPY_M10;
                              }
                              break;
                          case RLE_ESC_FB:
                              BUFFER_PRECHECK;
                              code = bytestream_get_byte(data_ptr);
                              rle_blocks = (code & 0x1F) - 1; /* set block counter */
                              if (code >= 64 || rle_blocks < 0)
                                  return IV3_BAD_COUNTER;
                              skip_flag = code & 0x20;
                              num_lines = 4 - line; /* enforce next block processing */
                              if (mode >= 10 || (cell->mv_ptr || !skip_flag)) {
                                  if (mode <= 4) {
                                      RLE_LINES_COPY;
                                  } else if (mode == 10 && !cell->mv_ptr) {
                                      RLE_LINES_COPY_M10;
                                  }
                              }
                              break;
                          case RLE_ESC_F9:
                              skip_flag  = 1;
                              rle_blocks = 1;
                              /* FALLTHROUGH */
                          case RLE_ESC_FA:
                              if (line)
                                  return IV3_BAD_RLE;
                              num_lines = 4; /* enforce next block processing */
                              if (cell->mv_ptr) {
                                  if (mode <= 4) {
                                      RLE_LINES_COPY;
                                  } else if (mode == 10 && !cell->mv_ptr) {
                                      RLE_LINES_COPY_M10;
                                  }
                              }
                              break;
                          default:
                              return IV3_UNSUPPORTED;
                          }
                      }
  
                      line += num_lines;
                      ref  += row_offset * (num_lines << v_zoom);
                      dst  += row_offset * (num_lines << v_zoom);
                  }
              }
  
              /* move to next horizontal block */
              block     += 4 << h_zoom;
              ref_block += 4 << h_zoom;
          }
  
          /* move to next line of blocks */
          ref_block += blk_row_offset;
          block     += blk_row_offset;
      }
      return IV3_NOERR;
  }
  
  
  /**
   *  Decode a vector-quantized cell.
   *  It consists of several routines, each of which handles one or more "modes"
   *  with which a cell can be encoded.
   *
   *  @param ctx      pointer to the decoder context
   *  @param avctx    ptr to the AVCodecContext
   *  @param plane    pointer to the plane descriptor
   *  @param cell     pointer to the cell  descriptor
   *  @param data_ptr pointer to the compressed data
   *  @param last_ptr pointer to the last byte to catch reads past end of buffer
   *  @return         number of consumed bytes or negative number in case of error
   */
  static int decode_cell(Indeo3DecodeContext *ctx, AVCodecContext *avctx,
                         Plane *plane, Cell *cell, const uint8_t *data_ptr,
                         const uint8_t *last_ptr)
  {
      int           x, mv_x, mv_y, mode, vq_index, prim_indx, second_indx;
      int           zoom_fac;
      int           offset, error = 0, swap_quads[2];
      uint8_t       code, *block, *ref_block = 0;
      const vqEntry *delta[2];
      const uint8_t *data_start = data_ptr;
  
      /* get coding mode and VQ table index from the VQ descriptor byte */
      code     = *data_ptr++;
      mode     = code >> 4;
      vq_index = code & 0xF;
  
      /* setup output and reference pointers */
      offset = (cell->ypos << 2) * plane->pitch + (cell->xpos << 2);
      block  =  plane->pixels[ctx->buf_sel] + offset;
  
      if (cell->mv_ptr) {
          mv_y      = cell->mv_ptr[0];
          mv_x      = cell->mv_ptr[1];
          if (   mv_x + 4*cell->xpos < 0
              || mv_y + 4*cell->ypos < 0
              || mv_x + 4*cell->xpos + 4*cell->width  > plane->width
              || mv_y + 4*cell->ypos + 4*cell->height > plane->height) {
              av_log(avctx, AV_LOG_ERROR, "motion vector %d %d outside reference\n", mv_x + 4*cell->xpos, mv_y + 4*cell->ypos);
              return AVERROR_INVALIDDATA;
          }
      }
  
      if (!cell->mv_ptr) {
          /* use previous line as reference for INTRA cells */
          ref_block = block - plane->pitch;
      } else if (mode >= 10) {
          /* for mode 10 and 11 INTER first copy the predicted cell into the current one */
          /* so we don't need to do data copying for each RLE code later */
          copy_cell(ctx, plane, cell);
      } else {
          /* set the pointer to the reference pixels for modes 0-4 INTER */
          mv_y      = cell->mv_ptr[0];
          mv_x      = cell->mv_ptr[1];
          offset   += mv_y * plane->pitch + mv_x;
          ref_block = plane->pixels[ctx->buf_sel ^ 1] + offset;
      }
  
      /* select VQ tables as follows: */
      /* modes 0 and 3 use only the primary table for all lines in a block */
      /* while modes 1 and 4 switch between primary and secondary tables on alternate lines */
      if (mode == 1 || mode == 4) {
          code        = ctx->alt_quant[vq_index];
          prim_indx   = (code >> 4)  + ctx->cb_offset;
          second_indx = (code & 0xF) + ctx->cb_offset;
      } else {
          vq_index += ctx->cb_offset;
          prim_indx = second_indx = vq_index;
      }
  
      if (prim_indx >= 24 || second_indx >= 24) {
          av_log(avctx, AV_LOG_ERROR, "Invalid VQ table indexes! Primary: %d, secondary: %d!\n",
                 prim_indx, second_indx);
          return AVERROR_INVALIDDATA;
      }
  
      delta[0] = &vq_tab[second_indx];
      delta[1] = &vq_tab[prim_indx];
      swap_quads[0] = second_indx >= 16;
      swap_quads[1] = prim_indx   >= 16;
  
      /* requantize the prediction if VQ index of this cell differs from VQ index */
      /* of the predicted cell in order to avoid overflows. */
      if (vq_index >= 8 && ref_block) {
          for (x = 0; x < cell->width << 2; x++)
              ref_block[x] = requant_tab[vq_index & 7][ref_block[x] & 127];
      }
  
      error = IV3_NOERR;
  
      switch (mode) {
      case 0: /*------------------ MODES 0 & 1 (4x4 block processing) --------------------*/
      case 1:
      case 3: /*------------------ MODES 3 & 4 (4x8 block processing) --------------------*/
      case 4:
          if (mode >= 3 && cell->mv_ptr) {
              av_log(avctx, AV_LOG_ERROR, "Attempt to apply Mode 3/4 to an INTER cell!\n");
              return AVERROR_INVALIDDATA;
          }
  
          zoom_fac = mode >= 3;
          error = decode_cell_data(cell, block, ref_block, plane->pitch, 0, zoom_fac,
                                   mode, delta, swap_quads, &data_ptr, last_ptr);
          break;
      case 10: /*-------------------- MODE 10 (8x8 block processing) ---------------------*/
      case 11: /*----------------- MODE 11 (4x8 INTER block processing) ------------------*/
          if (mode == 10 && !cell->mv_ptr) { /* MODE 10 INTRA processing */
              error = decode_cell_data(cell, block, ref_block, plane->pitch, 1, 1,
                                       mode, delta, swap_quads, &data_ptr, last_ptr);
          } else { /* mode 10 and 11 INTER processing */
              if (mode == 11 && !cell->mv_ptr) {
                 av_log(avctx, AV_LOG_ERROR, "Attempt to use Mode 11 for an INTRA cell!\n");
                 return AVERROR_INVALIDDATA;
              }
  
              zoom_fac = mode == 10;
              error = decode_cell_data(cell, block, ref_block, plane->pitch,
                                       zoom_fac, 1, mode, delta, swap_quads,
                                       &data_ptr, last_ptr);
          }
          break;
      default:
          av_log(avctx, AV_LOG_ERROR, "Unsupported coding mode: %d\n", mode);
          return AVERROR_INVALIDDATA;
      }//switch mode
  
      switch (error) {
      case IV3_BAD_RLE:
          av_log(avctx, AV_LOG_ERROR, "Mode %d: RLE code %X is not allowed at the current line\n",
                 mode, data_ptr[-1]);
          return AVERROR_INVALIDDATA;
      case IV3_BAD_DATA:
          av_log(avctx, AV_LOG_ERROR, "Mode %d: invalid VQ data\n", mode);
          return AVERROR_INVALIDDATA;
      case IV3_BAD_COUNTER:
          av_log(avctx, AV_LOG_ERROR, "Mode %d: RLE-FB invalid counter: %d\n", mode, code);
          return AVERROR_INVALIDDATA;
      case IV3_UNSUPPORTED:
          av_log(avctx, AV_LOG_ERROR, "Mode %d: unsupported RLE code: %X\n", mode, data_ptr[-1]);
          return AVERROR_INVALIDDATA;
      case IV3_OUT_OF_DATA:
          av_log(avctx, AV_LOG_ERROR, "Mode %d: attempt to read past end of buffer\n", mode);
          return AVERROR_INVALIDDATA;
      }
  
      return data_ptr - data_start; /* report number of bytes consumed from the input buffer */
  }
  
  
  /* Binary tree codes. */
  enum {
      H_SPLIT    = 0,
      V_SPLIT    = 1,
      INTRA_NULL = 2,
      INTER_DATA = 3
  };
  
  
  #define SPLIT_CELL(size, new_size) (new_size) = ((size) > 2) ? ((((size) + 2) >> 2) << 1) : 1
  
  #define UPDATE_BITPOS(n) \
      ctx->skip_bits  += (n); \
      ctx->need_resync = 1
  
  #define RESYNC_BITSTREAM \
      if (ctx->need_resync && !(get_bits_count(&ctx->gb) & 7)) { \
          skip_bits_long(&ctx->gb, ctx->skip_bits);              \
          ctx->skip_bits   = 0;                                  \
          ctx->need_resync = 0;                                  \
      }
  
  #define CHECK_CELL \
      if (curr_cell.xpos + curr_cell.width > (plane->width >> 2) ||               \
          curr_cell.ypos + curr_cell.height > (plane->height >> 2)) {             \
          av_log(avctx, AV_LOG_ERROR, "Invalid cell: x=%d, y=%d, w=%d, h=%d\n",   \
                 curr_cell.xpos, curr_cell.ypos, curr_cell.width, curr_cell.height); \
          return AVERROR_INVALIDDATA;                                                              \
      }
  
  
  static int parse_bintree(Indeo3DecodeContext *ctx, AVCodecContext *avctx,
                           Plane *plane, int code, Cell *ref_cell,
                           const int depth, const int strip_width)
  {
      Cell    curr_cell;
      int     bytes_used;
      int mv_x, mv_y;
  
      if (depth <= 0) {
          av_log(avctx, AV_LOG_ERROR, "Stack overflow (corrupted binary tree)!\n");
          return AVERROR_INVALIDDATA; // unwind recursion
      }
  
      curr_cell = *ref_cell; // clone parent cell
      if (code == H_SPLIT) {
          SPLIT_CELL(ref_cell->height, curr_cell.height);
          ref_cell->ypos   += curr_cell.height;
          ref_cell->height -= curr_cell.height;
          if (ref_cell->height <= 0 || curr_cell.height <= 0)
              return AVERROR_INVALIDDATA;
      } else if (code == V_SPLIT) {
          if (curr_cell.width > strip_width) {
              /* split strip */
              curr_cell.width = (curr_cell.width <= (strip_width << 1) ? 1 : 2) * strip_width;
          } else
              SPLIT_CELL(ref_cell->width, curr_cell.width);
          ref_cell->xpos  += curr_cell.width;
          ref_cell->width -= curr_cell.width;
          if (ref_cell->width <= 0 || curr_cell.width <= 0)
              return AVERROR_INVALIDDATA;
      }
  
      while (get_bits_left(&ctx->gb) >= 2) { /* loop until return */
          RESYNC_BITSTREAM;
          switch (code = get_bits(&ctx->gb, 2)) {
          case H_SPLIT:
          case V_SPLIT:
              if (parse_bintree(ctx, avctx, plane, code, &curr_cell, depth - 1, strip_width))
                  return AVERROR_INVALIDDATA;
              break;
          case INTRA_NULL:
              if (!curr_cell.tree) { /* MC tree INTRA code */
                  curr_cell.mv_ptr = 0; /* mark the current strip as INTRA */
                  curr_cell.tree   = 1; /* enter the VQ tree */
              } else { /* VQ tree NULL code */
                  RESYNC_BITSTREAM;
                  code = get_bits(&ctx->gb, 2);
                  if (code >= 2) {
                      av_log(avctx, AV_LOG_ERROR, "Invalid VQ_NULL code: %d\n", code);
                      return AVERROR_INVALIDDATA;
                  }
                  if (code == 1)
                      av_log(avctx, AV_LOG_ERROR, "SkipCell procedure not implemented yet!\n");
  
                  CHECK_CELL
                  if (!curr_cell.mv_ptr)
                      return AVERROR_INVALIDDATA;
  
                  mv_y = curr_cell.mv_ptr[0];
                  mv_x = curr_cell.mv_ptr[1];
                  if (   mv_x + 4*curr_cell.xpos < 0
                      || mv_y + 4*curr_cell.ypos < 0
                      || mv_x + 4*curr_cell.xpos + 4*curr_cell.width  > plane->width
                      || mv_y + 4*curr_cell.ypos + 4*curr_cell.height > plane->height) {
                      av_log(avctx, AV_LOG_ERROR, "motion vector %d %d outside reference\n", mv_x + 4*curr_cell.xpos, mv_y + 4*curr_cell.ypos);
                      return AVERROR_INVALIDDATA;
                  }
  
                  copy_cell(ctx, plane, &curr_cell);
                  return 0;
              }
              break;
          case INTER_DATA:
              if (!curr_cell.tree) { /* MC tree INTER code */
                  unsigned mv_idx;
                  /* get motion vector index and setup the pointer to the mv set */
                  if (!ctx->need_resync)
                      ctx->next_cell_data = &ctx->gb.buffer[(get_bits_count(&ctx->gb) + 7) >> 3];
                  if (ctx->next_cell_data >= ctx->last_byte) {
                      av_log(avctx, AV_LOG_ERROR, "motion vector out of array\n");
                      return AVERROR_INVALIDDATA;
                  }
                  mv_idx = *(ctx->next_cell_data++);
                  if (mv_idx >= ctx->num_vectors) {
                      av_log(avctx, AV_LOG_ERROR, "motion vector index out of range\n");
                      return AVERROR_INVALIDDATA;
                  }
                  curr_cell.mv_ptr = &ctx->mc_vectors[mv_idx << 1];
                  curr_cell.tree   = 1; /* enter the VQ tree */
                  UPDATE_BITPOS(8);
              } else { /* VQ tree DATA code */
                  if (!ctx->need_resync)
                      ctx->next_cell_data = &ctx->gb.buffer[(get_bits_count(&ctx->gb) + 7) >> 3];
  
                  CHECK_CELL
                  bytes_used = decode_cell(ctx, avctx, plane, &curr_cell,
                                           ctx->next_cell_data, ctx->last_byte);
                  if (bytes_used < 0)
                      return AVERROR_INVALIDDATA;
  
                  UPDATE_BITPOS(bytes_used << 3);
                  ctx->next_cell_data += bytes_used;
                  return 0;
              }
              break;
          }
      }//while
  
      return AVERROR_INVALIDDATA;
  }
  
  
  static int decode_plane(Indeo3DecodeContext *ctx, AVCodecContext *avctx,
                          Plane *plane, const uint8_t *data, int32_t data_size,
                          int32_t strip_width)
  {
      Cell            curr_cell;
      unsigned        num_vectors;
  
      /* each plane data starts with mc_vector_count field, */
      /* an optional array of motion vectors followed by the vq data */
      num_vectors = bytestream_get_le32(&data); data_size -= 4;
      if (num_vectors > 256) {
          av_log(ctx->avctx, AV_LOG_ERROR,
                 "Read invalid number of motion vectors %d\n", num_vectors);
          return AVERROR_INVALIDDATA;
      }
      if (num_vectors * 2 > data_size)
          return AVERROR_INVALIDDATA;
  
      ctx->num_vectors = num_vectors;
      ctx->mc_vectors  = num_vectors ? data : 0;
  
      /* init the bitreader */
      init_get_bits(&ctx->gb, &data[num_vectors * 2], (data_size - num_vectors * 2) << 3);
      ctx->skip_bits   = 0;
      ctx->need_resync = 0;
  
      ctx->last_byte = data + data_size;
  
      /* initialize the 1st cell and set its dimensions to whole plane */
      curr_cell.xpos   = curr_cell.ypos = 0;
      curr_cell.width  = plane->width  >> 2;
      curr_cell.height = plane->height >> 2;
      curr_cell.tree   = 0; // we are in the MC tree now
      curr_cell.mv_ptr = 0; // no motion vector = INTRA cell
  
      return parse_bintree(ctx, avctx, plane, INTRA_NULL, &curr_cell, CELL_STACK_MAX, strip_width);
  }
  
  
  #define OS_HDR_ID   MKBETAG('F', 'R', 'M', 'H')
  
  static int decode_frame_headers(Indeo3DecodeContext *ctx, AVCodecContext *avctx,
                                  const uint8_t *buf, int buf_size)
  {
      const uint8_t   *buf_ptr = buf, *bs_hdr;
      uint32_t        frame_num, word2, check_sum, data_size;
      uint32_t        y_offset, u_offset, v_offset, starts[3], ends[3];
      uint16_t        height, width;
      int             i, j;
  
      /* parse and check the OS header */
      frame_num = bytestream_get_le32(&buf_ptr);
      word2     = bytestream_get_le32(&buf_ptr);
      check_sum = bytestream_get_le32(&buf_ptr);
      data_size = bytestream_get_le32(&buf_ptr);
  
      if ((frame_num ^ word2 ^ data_size ^ OS_HDR_ID) != check_sum) {
          av_log(avctx, AV_LOG_ERROR, "OS header checksum mismatch!\n");
          return AVERROR_INVALIDDATA;
      }
  
      /* parse the bitstream header */
      bs_hdr = buf_ptr;
      buf_size -= 16;
  
      if (bytestream_get_le16(&buf_ptr) != 32) {
          av_log(avctx, AV_LOG_ERROR, "Unsupported codec version!\n");
          return AVERROR_INVALIDDATA;
      }
  
      ctx->frame_num   =  frame_num;
      ctx->frame_flags =  bytestream_get_le16(&buf_ptr);
      ctx->data_size   = (bytestream_get_le32(&buf_ptr) + 7) >> 3;
      ctx->cb_offset   = *buf_ptr++;
  
      if (ctx->data_size == 16)
          return 4;
      if (ctx->data_size > buf_size)
          ctx->data_size = buf_size;
  
      buf_ptr += 3; // skip reserved byte and checksum
  
      /* check frame dimensions */
      height = bytestream_get_le16(&buf_ptr);
      width  = bytestream_get_le16(&buf_ptr);
      if (av_image_check_size(width, height, 0, avctx))
          return AVERROR_INVALIDDATA;
  
      if (width != ctx->width || height != ctx->height) {
          int res;
  
          av_dlog(avctx, "Frame dimensions changed!\n");
  
          if (width  < 16 || width  > 640 ||
              height < 16 || height > 480 ||
              width  &  3 || height &   3) {
              av_log(avctx, AV_LOG_ERROR,
                     "Invalid picture dimensions: %d x %d!\n", width, height);
              return AVERROR_INVALIDDATA;
          }
          free_frame_buffers(ctx);
          if ((res = allocate_frame_buffers(ctx, avctx, width, height)) < 0)
               return res;
          avcodec_set_dimensions(avctx, width, height);
      }
  
      y_offset = bytestream_get_le32(&buf_ptr);
      v_offset = bytestream_get_le32(&buf_ptr);
      u_offset = bytestream_get_le32(&buf_ptr);
  
      /* unfortunately there is no common order of planes in the buffer */
      /* so we use that sorting algo for determining planes data sizes  */
      starts[0] = y_offset;
      starts[1] = v_offset;
      starts[2] = u_offset;
  
      for (j = 0; j < 3; j++) {
          ends[j] = ctx->data_size;
          for (i = 2; i >= 0; i--)
              if (starts[i] < ends[j] && starts[i] > starts[j])
                  ends[j] = starts[i];
      }
  
      ctx->y_data_size = ends[0] - starts[0];
      ctx->v_data_size = ends[1] - starts[1];
      ctx->u_data_size = ends[2] - starts[2];
      if (FFMAX3(y_offset, v_offset, u_offset) >= ctx->data_size - 16 ||
          FFMIN3(ctx->y_data_size, ctx->v_data_size, ctx->u_data_size) <= 0) {
          av_log(avctx, AV_LOG_ERROR, "One of the y/u/v offsets is invalid\n");
          return AVERROR_INVALIDDATA;
      }
  
      ctx->y_data_ptr = bs_hdr + y_offset;
      ctx->v_data_ptr = bs_hdr + v_offset;
      ctx->u_data_ptr = bs_hdr + u_offset;
      ctx->alt_quant  = buf_ptr + sizeof(uint32_t);
  
      if (ctx->data_size == 16) {
          av_log(avctx, AV_LOG_DEBUG, "Sync frame encountered!\n");
          return 16;
      }
  
      if (ctx->frame_flags & BS_8BIT_PEL) {
          av_log_ask_for_sample(avctx, "8-bit pixel format\n");
          return AVERROR_PATCHWELCOME;
      }
  
      if (ctx->frame_flags & BS_MV_X_HALF || ctx->frame_flags & BS_MV_Y_HALF) {
          av_log_ask_for_sample(avctx, "halfpel motion vectors\n");
          return AVERROR_PATCHWELCOME;
      }
  
      return 0;
  }
  
  
  /**
   *  Convert and output the current plane.
   *  All pixel values will be upsampled by shifting right by one bit.
   *
   *  @param[in]  plane        pointer to the descriptor of the plane being processed
   *  @param[in]  buf_sel      indicates which frame buffer the input data stored in
   *  @param[out] dst          pointer to the buffer receiving converted pixels
   *  @param[in]  dst_pitch    pitch for moving to the next y line
   *  @param[in]  dst_height   output plane height
   */
  static void output_plane(const Plane *plane, int buf_sel, uint8_t *dst,
                           int dst_pitch, int dst_height)
  {
      int             x,y;
      const uint8_t   *src  = plane->pixels[buf_sel];
      uint32_t        pitch = plane->pitch;
  
      dst_height = FFMIN(dst_height, plane->height);
      for (y = 0; y < dst_height; y++) {
          /* convert four pixels at once using SWAR */
          for (x = 0; x < plane->width >> 2; x++) {
              AV_WN32A(dst, (AV_RN32A(src) & 0x7F7F7F7F) << 1);
              src += 4;
              dst += 4;
          }
  
          for (x <<= 2; x < plane->width; x++)
              *dst++ = *src++ << 1;
  
          src += pitch     - plane->width;
          dst += dst_pitch - plane->width;
      }
  }
  
  
  static av_cold int decode_init(AVCodecContext *avctx)
  {
      Indeo3DecodeContext *ctx = avctx->priv_data;
  
      ctx->avctx     = avctx;
      avctx->pix_fmt = AV_PIX_FMT_YUV410P;
      avcodec_get_frame_defaults(&ctx->frame);
  
      build_requant_tab();
  
      ff_dsputil_init(&ctx->dsp, avctx);
  
      return allocate_frame_buffers(ctx, avctx, avctx->width, avctx->height);
  }
  
  
  static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
                          AVPacket *avpkt)
  {
      Indeo3DecodeContext *ctx = avctx->priv_data;
      const uint8_t *buf = avpkt->data;
      int buf_size       = avpkt->size;
      int res;
  
      res = decode_frame_headers(ctx, avctx, buf, buf_size);
      if (res < 0)
          return res;
  
      /* skip sync(null) frames */
      if (res) {
          // we have processed 16 bytes but no data was decoded
          *got_frame = 0;
          return buf_size;
      }
  
      /* skip droppable INTER frames if requested */
      if (ctx->frame_flags & BS_NONREF &&
         (avctx->skip_frame >= AVDISCARD_NONREF))
          return 0;
  
      /* skip INTER frames if requested */
      if (!(ctx->frame_flags & BS_KEYFRAME) && avctx->skip_frame >= AVDISCARD_NONKEY)
          return 0;
  
      /* use BS_BUFFER flag for buffer switching */
      ctx->buf_sel = (ctx->frame_flags >> BS_BUFFER) & 1;
  
      if (ctx->frame.data[0])
          avctx->release_buffer(avctx, &ctx->frame);
  
      ctx->frame.reference = 0;
      if ((res = ff_get_buffer(avctx, &ctx->frame)) < 0) {
          av_log(ctx->avctx, AV_LOG_ERROR, "get_buffer() failed\n");
          return res;
      }
  
      /* decode luma plane */
      if ((res = decode_plane(ctx, avctx, ctx->planes, ctx->y_data_ptr, ctx->y_data_size, 40)))
          return res;
  
      /* decode chroma planes */
      if ((res = decode_plane(ctx, avctx, &ctx->planes[1], ctx->u_data_ptr, ctx->u_data_size, 10)))
          return res;
  
      if ((res = decode_plane(ctx, avctx, &ctx->planes[2], ctx->v_data_ptr, ctx->v_data_size, 10)))
          return res;
  
      output_plane(&ctx->planes[0], ctx->buf_sel,
                   ctx->frame.data[0], ctx->frame.linesize[0],
                   avctx->height);
      output_plane(&ctx->planes[1], ctx->buf_sel,
                   ctx->frame.data[1], ctx->frame.linesize[1],
                   (avctx->height + 3) >> 2);
      output_plane(&ctx->planes[2], ctx->buf_sel,
                   ctx->frame.data[2], ctx->frame.linesize[2],
                   (avctx->height + 3) >> 2);
  
      *got_frame = 1;
      *(AVFrame*)data = ctx->frame;
  
      return buf_size;
  }
  
  
  static av_cold int decode_close(AVCodecContext *avctx)
  {
      Indeo3DecodeContext *ctx = avctx->priv_data;
  
      free_frame_buffers(avctx->priv_data);
  
      if (ctx->frame.data[0])
          avctx->release_buffer(avctx, &ctx->frame);
  
      return 0;
  }
  
  AVCodec ff_indeo3_decoder = {
      .name           = "indeo3",
      .type           = AVMEDIA_TYPE_VIDEO,
      .id             = AV_CODEC_ID_INDEO3,
      .priv_data_size = sizeof(Indeo3DecodeContext),
      .init           = decode_init,
      .close          = decode_close,
      .decode         = decode_frame,
      .long_name      = NULL_IF_CONFIG_SMALL("Intel Indeo 3"),
      .capabilities   = CODEC_CAP_DR1,
  };
  