text: /*
   * ClearVideo decoder
   * Copyright (c) 2012 Konstantin Shishkov
   *
   * 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
   * ClearVideo decoder
   */
  
  #include "avcodec.h"
  #include "idctdsp.h"
  #include "internal.h"
  #include "get_bits.h"
  #include "bytestream.h"
  
  #define NUM_DC_CODES 127
  #define NUM_AC_CODES 103
  
  static const uint8_t clv_dc_codes[NUM_DC_CODES] = {
      0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
      0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F,
      0x10, 0x11, 0x12, 0x13, 0x13, 0x14, 0x07, 0x0B,
      0x0C, 0x08, 0x08, 0x09, 0x04, 0x06, 0x07, 0x05,
      0x04, 0x05, 0x04, 0x06, 0x05, 0x06, 0x07, 0x05,
      0x06, 0x07, 0x06, 0x07, 0x08, 0x06, 0x07, 0x08,
      0x09, 0x0A, 0x0B, 0x07, 0x08, 0x09, 0x07, 0x08,
      0x06, 0x07, 0x08, 0x06, 0x04, 0x05, 0x02, 0x01,
      0x03, 0x06, 0x07, 0x07, 0x09, 0x0A, 0x0B, 0x09,
      0x0A, 0x0B, 0x0A, 0x0B, 0x0C, 0x0D, 0x0C, 0x09,
      0x0D, 0x0A, 0x0B, 0x08, 0x09, 0x0A, 0x0B, 0x07,
      0x08, 0x09, 0x0A, 0x0B, 0x06, 0x07, 0x06, 0x08,
      0x07, 0x09, 0x0A, 0x0B, 0x09, 0x0A, 0x0B, 0x0C,
      0x14, 0x0D, 0x0D, 0x0E, 0x0F, 0x15, 0x15, 0x16,
      0x17, 0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E,
      0x1F, 0x20, 0x21, 0x22, 0x23, 0x24, 0x25,
  };
  
  static const uint8_t clv_dc_bits[NUM_DC_CODES] = {
      22, 22, 22, 22, 22, 22, 22, 22,
      22, 22, 22, 22, 22, 22, 22, 22,
      22, 22, 22, 21, 22, 22, 19, 20,
      20, 19, 18, 18, 15, 17, 17, 16,
      14, 15, 12, 13, 14, 14, 14, 12,
      12, 12, 11, 11, 11, 10, 10, 10,
      10, 10, 10,  9,  9,  9,  8,  8,
       7,  7,  7,  6,  5,  5,  3,  1,
       3,  5,  5,  6,  7,  7,  7,  8,
       8,  8,  9,  9,  9,  9, 10, 11,
      10, 11, 11, 12, 12, 12, 12, 13,
      14, 14, 14, 14, 15, 15, 16, 17,
      16, 17, 18, 18, 19, 19, 19, 19,
      21, 19, 20, 19, 19, 21, 22, 22,
      22, 22, 22, 22, 22, 22, 22, 22,
      22, 22, 22, 22, 22, 22, 22,
  };
  
  static const uint16_t clv_ac_syms[NUM_AC_CODES] = {
      0x0001, 0x0002, 0x0003, 0x0004, 0x0005, 0x0006, 0x0007, 0x0008,
      0x0009, 0x000A, 0x000B, 0x000C, 0x0011, 0x0012, 0x0013, 0x0014,
      0x0015, 0x0016, 0x0021, 0x0022, 0x0023, 0x0024, 0x0031, 0x0032,
      0x0033, 0x0041, 0x0042, 0x0043, 0x0051, 0x0052, 0x0053, 0x0061,
      0x0062, 0x0063, 0x0071, 0x0072, 0x0081, 0x0082, 0x0091, 0x0092,
      0x00A1, 0x00A2, 0x00B1, 0x00C1, 0x00D1, 0x00E1, 0x00F1, 0x0101,
      0x0111, 0x0121, 0x0131, 0x0141, 0x0151, 0x0161, 0x0171, 0x0181,
      0x0191, 0x01A1, 0x1001, 0x1002, 0x1003, 0x1011, 0x1012, 0x1021,
      0x1031, 0x1041, 0x1051, 0x1061, 0x1071, 0x1081, 0x1091, 0x10A1,
      0x10B1, 0x10C1, 0x10D1, 0x10E1, 0x10F1, 0x1101, 0x1111, 0x1121,
      0x1131, 0x1141, 0x1151, 0x1161, 0x1171, 0x1181, 0x1191, 0x11A1,
      0x11B1, 0x11C1, 0x11D1, 0x11E1, 0x11F1, 0x1201, 0x1211, 0x1221,
      0x1231, 0x1241, 0x1251, 0x1261, 0x1271, 0x1281, 0x1BFF,
  };
  
  static const uint8_t clv_ac_codes[NUM_AC_CODES] = {
      0x02, 0x0F, 0x15, 0x17, 0x1F, 0x25, 0x24, 0x21,
      0x20, 0x07, 0x06, 0x20, 0x06, 0x14, 0x1E, 0x0F,
      0x21, 0x50, 0x0E, 0x1D, 0x0E, 0x51, 0x0D, 0x23,
      0x0D, 0x0C, 0x22, 0x52, 0x0B, 0x0C, 0x53, 0x13,
      0x0B, 0x54, 0x12, 0x0A, 0x11, 0x09, 0x10, 0x08,
      0x16, 0x55, 0x15, 0x14, 0x1C, 0x1B, 0x21, 0x20,
      0x1F, 0x1E, 0x1D, 0x1C, 0x1B, 0x1A, 0x22, 0x23,
      0x56, 0x57, 0x07, 0x19, 0x05, 0x0F, 0x04, 0x0E,
      0x0D, 0x0C, 0x13, 0x12, 0x11, 0x10, 0x1A, 0x19,
      0x18, 0x17, 0x16, 0x15, 0x14, 0x13, 0x18, 0x17,
      0x16, 0x15, 0x14, 0x13, 0x12, 0x11, 0x07, 0x06,
      0x05, 0x04, 0x24, 0x25, 0x26, 0x27, 0x58, 0x59,
      0x5A, 0x5B, 0x5C, 0x5D, 0x5E, 0x5F, 0x03,
  };
  
  static const uint8_t clv_ac_bits[NUM_AC_CODES] = {
       2,  4,  6,  7,  8,  9,  9, 10,
      10, 11, 11, 11,  3,  6,  8, 10,
      11, 12,  4,  8, 10, 12,  5,  9,
      10,  5,  9, 12,  5, 10, 12,  6,
      10, 12,  6, 10,  6, 10,  6, 10,
       7, 12,  7,  7,  8,  8,  9,  9,
       9,  9,  9,  9,  9,  9, 11, 11,
      12, 12,  4,  9, 11,  6, 11,  6,
       6,  6,  7,  7,  7,  7,  8,  8,
       8,  8,  8,  8,  8,  8,  9,  9,
       9,  9,  9,  9,  9,  9, 10, 10,
      10, 10, 11, 11, 11, 11, 12, 12,
      12, 12, 12, 12, 12, 12,  7,
  };
  
  typedef struct CLVContext {
      AVCodecContext *avctx;
      IDCTDSPContext idsp;
      AVFrame        *pic;
      GetBitContext  gb;
      int            mb_width, mb_height;
      VLC            dc_vlc, ac_vlc;
      int            luma_dc_quant, chroma_dc_quant, ac_quant;
      DECLARE_ALIGNED(16, int16_t, block)[64];
      int            top_dc[3], left_dc[4];
  } CLVContext;
  
  static inline int decode_block(CLVContext *ctx, int16_t *blk, int has_ac,
                                 int ac_quant)
  {
      GetBitContext *gb = &ctx->gb;
      int idx = 1, last = 0, val, skip;
  
      memset(blk, 0, sizeof(*blk) * 64);
      blk[0] = get_vlc2(gb, ctx->dc_vlc.table, 9, 3);
      if (blk[0] < 0)
          return AVERROR_INVALIDDATA;
      blk[0] -= 63;
  
      if (!has_ac)
          return 0;
  
      while (idx < 64 && !last) {
          val = get_vlc2(gb, ctx->ac_vlc.table, 9, 2);
          if (val < 0)
              return AVERROR_INVALIDDATA;
          if (val != 0x1BFF) {
              last =  val >> 12;
              skip = (val >> 4) & 0xFF;
              val &= 0xF;
              if (get_bits1(gb))
                  val = -val;
          } else {
              last = get_bits1(gb);
              skip = get_bits(gb, 6);
              val  = get_sbits(gb, 8);
          }
          if (val) {
              int aval = FFABS(val), sign = val < 0;
              val = ac_quant * (2 * aval + 1);
              if (!(ac_quant & 1))
                  val--;
              if (sign)
                  val = -val;
          }
          idx += skip;
          if (idx >= 64)
              return AVERROR_INVALIDDATA;
          blk[ff_zigzag_direct[idx++]] = val;
      }
  
      return (idx <= 64 && last) ? 0 : -1;
  }
  
  #define DCT_TEMPLATE(blk, step, bias, shift, dshift, OP)                \
      const int t0 = OP( 2841 * blk[1 * step] +  565 * blk[7 * step]);    \
      const int t1 = OP(  565 * blk[1 * step] - 2841 * blk[7 * step]);    \
      const int t2 = OP( 1609 * blk[5 * step] + 2408 * blk[3 * step]);    \
      const int t3 = OP( 2408 * blk[5 * step] - 1609 * blk[3 * step]);    \
      const int t4 = OP( 1108 * blk[2 * step] - 2676 * blk[6 * step]);    \
      const int t5 = OP( 2676 * blk[2 * step] + 1108 * blk[6 * step]);    \
      const int t6 = ((blk[0 * step] + blk[4 * step]) * (1 << dshift)) + bias;  \
      const int t7 = ((blk[0 * step] - blk[4 * step]) * (1 << dshift)) + bias;  \
      const int t8 = t0 + t2;                                             \
      const int t9 = t0 - t2;                                             \
      const int tA = 181 * (t9 + (t1 - t3)) + 0x80 >> 8;                  \
      const int tB = 181 * (t9 - (t1 - t3)) + 0x80 >> 8;                  \
      const int tC = t1 + t3;                                             \
                                                                          \
      blk[0 * step] = (t6 + t5 + t8) >> shift;                            \
      blk[1 * step] = (t7 + t4 + tA) >> shift;                            \
      blk[2 * step] = (t7 - t4 + tB) >> shift;                            \
      blk[3 * step] = (t6 - t5 + tC) >> shift;                            \
      blk[4 * step] = (t6 - t5 - tC) >> shift;                            \
      blk[5 * step] = (t7 - t4 - tB) >> shift;                            \
      blk[6 * step] = (t7 + t4 - tA) >> shift;                            \
      blk[7 * step] = (t6 + t5 - t8) >> shift;                            \
  
  #define ROP(x) x
  #define COP(x) (((x) + 4) >> 3)
  
  static void clv_dct(int16_t *block)
  {
      int i;
      int16_t *ptr;
  
      ptr = block;
      for (i = 0; i < 8; i++) {
          DCT_TEMPLATE(ptr, 1, 0x80, 8, 11, ROP);
          ptr += 8;
      }
  
      ptr = block;
      for (i = 0; i < 8; i++) {
          DCT_TEMPLATE(ptr, 8, 0x2000, 14, 8, COP);
          ptr++;
      }
  }
  
  static int decode_mb(CLVContext *c, int x, int y)
  {
      int i;
      int has_ac[6];
      int off;
  
      for (i = 0; i < 6; i++)
          has_ac[i] = get_bits1(&c->gb);
  
      off = x * 16 + y * 16 * c->pic->linesize[0];
      for (i = 0; i < 4; i++) {
          if (decode_block(c, c->block, has_ac[i], c->ac_quant) < 0)
              return AVERROR_INVALIDDATA;
          if (!x && !(i & 1)) {
              c->block[0] += c->top_dc[0];
              c->top_dc[0] = c->block[0];
          } else {
              c->block[0] += c->left_dc[(i & 2) >> 1];
          }
          c->left_dc[(i & 2) >> 1] = c->block[0];
          c->block[0]             *= c->luma_dc_quant;
          clv_dct(c->block);
          if (i == 2)
              off += c->pic->linesize[0] * 8;
          c->idsp.put_pixels_clamped(c->block, c->pic->data[0] + off + (i & 1) * 8,
                                     c->pic->linesize[0]);
      }
  
      off = x * 8 + y * 8 * c->pic->linesize[1];
      for (i = 1; i < 3; i++) {
          if (decode_block(c, c->block, has_ac[i + 3], c->ac_quant) < 0)
              return AVERROR_INVALIDDATA;
          if (!x) {
              c->block[0] += c->top_dc[i];
              c->top_dc[i] = c->block[0];
          } else {
              c->block[0] += c->left_dc[i + 1];
          }
          c->left_dc[i + 1] = c->block[0];
          c->block[0]      *= c->chroma_dc_quant;
          clv_dct(c->block);
          c->idsp.put_pixels_clamped(c->block, c->pic->data[i] + off,
                                     c->pic->linesize[i]);
      }
  
      return 0;
  }
  
  static int clv_decode_frame(AVCodecContext *avctx, void *data,
                              int *got_frame, AVPacket *avpkt)
  {
      const uint8_t *buf = avpkt->data;
      int buf_size = avpkt->size;
      CLVContext *c = avctx->priv_data;
      GetByteContext gb;
      uint32_t frame_type;
      int i, j;
      int ret;
      int mb_ret = 0;
  
      bytestream2_init(&gb, buf, buf_size);
      if (avctx->codec_tag == MKTAG('C','L','V','1')) {
          int skip = bytestream2_get_byte(&gb);
          bytestream2_skip(&gb, (skip + 1) * 8);
      }
  
      frame_type = bytestream2_get_byte(&gb);
      if ((ret = ff_reget_buffer(avctx, c->pic)) < 0)
          return ret;
  
      c->pic->key_frame = frame_type & 0x20 ? 1 : 0;
      c->pic->pict_type = frame_type & 0x20 ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;
  
      if (frame_type & 0x2) {
          bytestream2_get_be32(&gb); // frame size;
          c->ac_quant        = bytestream2_get_byte(&gb);
          c->luma_dc_quant   = 32;
          c->chroma_dc_quant = 32;
  
          if ((ret = init_get_bits8(&c->gb, buf + bytestream2_tell(&gb),
                                    (buf_size - bytestream2_tell(&gb)))) < 0)
              return ret;
  
          for (i = 0; i < 3; i++)
              c->top_dc[i] = 32;
          for (i = 0; i < 4; i++)
              c->left_dc[i] = 32;
  
          for (j = 0; j < c->mb_height; j++) {
              for (i = 0; i < c->mb_width; i++) {
                  ret = decode_mb(c, i, j);
                  if (ret < 0)
                      mb_ret = ret;
              }
          }
      } else {
      }
  
      if ((ret = av_frame_ref(data, c->pic)) < 0)
          return ret;
  
      *got_frame = 1;
  
      return mb_ret < 0 ? mb_ret : buf_size;
  }
  
  static av_cold int clv_decode_init(AVCodecContext *avctx)
  {
      CLVContext * const c = avctx->priv_data;
      int ret;
  
      c->avctx = avctx;
  
      avctx->pix_fmt = AV_PIX_FMT_YUV420P;
  
      c->pic = av_frame_alloc();
      if (!c->pic)
          return AVERROR(ENOMEM);
  
      c->mb_width  = FFALIGN(avctx->width,  16) >> 4;
      c->mb_height = FFALIGN(avctx->height, 16) >> 4;
  
      ff_idctdsp_init(&c->idsp, avctx);
      ret = init_vlc(&c->dc_vlc, 9, NUM_DC_CODES,
                     clv_dc_bits,  1, 1,
                     clv_dc_codes, 1, 1, 0);
      if (ret) {
          av_log(avctx, AV_LOG_ERROR, "Error initialising DC VLC\n");
          return ret;
      }
      ret = ff_init_vlc_sparse(&c->ac_vlc, 9, NUM_AC_CODES,
                               clv_ac_bits,  1, 1,
                               clv_ac_codes, 1, 1,
                               clv_ac_syms,  2, 2, 0);
      if (ret) {
          av_log(avctx, AV_LOG_ERROR, "Error initialising AC VLC\n");
          return ret;
      }
  
      return 0;
  }
  
  static av_cold int clv_decode_end(AVCodecContext *avctx)
  {
      CLVContext * const c = avctx->priv_data;
  
      av_frame_free(&c->pic);
  
      ff_free_vlc(&c->dc_vlc);
      ff_free_vlc(&c->ac_vlc);
  
      return 0;
  }
  
  AVCodec ff_clearvideo_decoder = {
      .name           = "clearvideo",
      .type           = AVMEDIA_TYPE_VIDEO,
      .id             = AV_CODEC_ID_CLEARVIDEO,
      .priv_data_size = sizeof(CLVContext),
      .init           = clv_decode_init,
      .close          = clv_decode_end,
      .decode         = clv_decode_frame,
      .capabilities   = AV_CODEC_CAP_DR1,
      .long_name      = NULL_IF_CONFIG_SMALL("Iterated Systems ClearVideo"),
  };
  