text: /*
   * Electronic Arts TGV Video Decoder
   * Copyright (c) 2007-2008 Peter Ross
   *
   * 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 St, Fifth Floor, Boston, MA  02110-1301  USA
   */
  
  /**
   * @file
   * Electronic Arts TGV Video Decoder
   * by Peter Ross (pross@xvid.org)
   *
   * Technical details here:
   * http://wiki.multimedia.cx/index.php?title=Electronic_Arts_TGV
   */
  
  #include "avcodec.h"
  #define BITSTREAM_READER_LE
  #include "get_bits.h"
  #include "internal.h"
  #include "libavutil/imgutils.h"
  #include "libavutil/mem.h"
  
  #define EA_PREAMBLE_SIZE    8
  #define kVGT_TAG MKTAG('k', 'V', 'G', 'T')
  
  typedef struct TgvContext {
      AVCodecContext *avctx;
      AVFrame last_frame;
      uint8_t *frame_buffer;
      int width,height;
      uint32_t palette[AVPALETTE_COUNT];
  
      int (*mv_codebook)[2];
      uint8_t (*block_codebook)[16];
      int num_mvs;           ///< current length of mv_codebook
      int num_blocks_packed; ///< current length of block_codebook
  } TgvContext;
  
  static av_cold int tgv_decode_init(AVCodecContext *avctx)
  {
      TgvContext *s = avctx->priv_data;
      s->avctx         = avctx;
      avctx->time_base = (AVRational){1, 15};
      avctx->pix_fmt   = AV_PIX_FMT_PAL8;
      avcodec_get_frame_defaults(&s->last_frame);
      return 0;
  }
  
  /**
   * Unpack buffer
   * @return 0 on success, -1 on critical buffer underflow
   */
  static int unpack(const uint8_t *src, const uint8_t *src_end,
                    uint8_t *dst, int width, int height)
  {
      uint8_t *dst_end = dst + width*height;
      int size, size1, size2, offset, run;
      uint8_t *dst_start = dst;
  
      if (src[0] & 0x01)
          src += 5;
      else
          src += 2;
  
      if (src_end - src < 3)
          return AVERROR_INVALIDDATA;
      size = AV_RB24(src);
      src += 3;
  
      while (size > 0 && src < src_end) {
  
          /* determine size1 and size2 */
          size1 = (src[0] & 3);
          if (src[0] & 0x80) {  // 1
              if (src[0] & 0x40 ) {  // 11
                  if (src[0] & 0x20) {  // 111
                      if (src[0] < 0xFC)  // !(111111)
                          size1 = (((src[0] & 31) + 1) << 2);
                      src++;
                      size2 = 0;
                  } else {  // 110
                      offset = ((src[0] & 0x10) << 12) + AV_RB16(&src[1]) + 1;
                      size2  = ((src[0] & 0xC) << 6) + src[3] + 5;
                      src   += 4;
                  }
              } else {  // 10
                  size1  = ((src[1] & 0xC0) >> 6);
                  offset = (AV_RB16(&src[1]) & 0x3FFF) + 1;
                  size2  = (src[0] & 0x3F) + 4;
                  src   += 3;
              }
          } else {  // 0
              offset = ((src[0] & 0x60) << 3) + src[1] + 1;
              size2  = ((src[0] & 0x1C) >> 2) + 3;
              src   += 2;
          }
  
  
          /* fetch strip from src */
          if (size1 > src_end - src)
              break;
  
          if (size1 > 0) {
              size -= size1;
              run   = FFMIN(size1, dst_end - dst);
              memcpy(dst, src, run);
              dst += run;
              src += run;
          }
  
          if (size2 > 0) {
              if (dst - dst_start < offset)
                  return 0;
              size -= size2;
              run   = FFMIN(size2, dst_end - dst);
              av_memcpy_backptr(dst, offset, run);
              dst += run;
          }
      }
  
      return 0;
  }
  
  /**
   * Decode inter-frame
   * @return 0 on success, -1 on critical buffer underflow
   */
  static int tgv_decode_inter(TgvContext *s, AVFrame *frame,
                              const uint8_t *buf, const uint8_t *buf_end)
  {
      int num_mvs;
      int num_blocks_raw;
      int num_blocks_packed;
      int vector_bits;
      int i,j,x,y;
      GetBitContext gb;
      int mvbits;
      const uint8_t *blocks_raw;
  
      if(buf_end - buf < 12)
          return AVERROR_INVALIDDATA;
  
      num_mvs           = AV_RL16(&buf[0]);
      num_blocks_raw    = AV_RL16(&buf[2]);
      num_blocks_packed = AV_RL16(&buf[4]);
      vector_bits       = AV_RL16(&buf[6]);
      buf += 12;
  
      if (vector_bits > MIN_CACHE_BITS || !vector_bits) {
          av_log(s->avctx, AV_LOG_ERROR,
                 "Invalid value for motion vector bits: %d\n", vector_bits);
          return AVERROR_INVALIDDATA;
      }
  
      /* allocate codebook buffers as necessary */
      if (num_mvs > s->num_mvs) {
          s->mv_codebook = av_realloc(s->mv_codebook, num_mvs*2*sizeof(int));
          s->num_mvs = num_mvs;
      }
  
      if (num_blocks_packed > s->num_blocks_packed) {
          s->block_codebook = av_realloc(s->block_codebook, num_blocks_packed*16);
          s->num_blocks_packed = num_blocks_packed;
      }
  
      /* read motion vectors */
      mvbits = (num_mvs * 2 * 10 + 31) & ~31;
  
      if (buf_end - buf < (mvbits>>3) + 16*num_blocks_raw + 8*num_blocks_packed)
          return AVERROR_INVALIDDATA;
  
      init_get_bits(&gb, buf, mvbits);
      for (i = 0; i < num_mvs; i++) {
          s->mv_codebook[i][0] = get_sbits(&gb, 10);
          s->mv_codebook[i][1] = get_sbits(&gb, 10);
      }
      buf += mvbits >> 3;
  
      /* note ptr to uncompressed blocks */
      blocks_raw = buf;
      buf       += num_blocks_raw * 16;
  
      /* read compressed blocks */
      init_get_bits(&gb, buf, (buf_end - buf) << 3);
      for (i = 0; i < num_blocks_packed; i++) {
          int tmp[4];
          for (j = 0; j < 4; j++)
              tmp[j] = get_bits(&gb, 8);
          for (j = 0; j < 16; j++)
              s->block_codebook[i][15-j] = tmp[get_bits(&gb, 2)];
      }
  
      if (get_bits_left(&gb) < vector_bits *
          (s->avctx->height / 4) * (s->avctx->width / 4))
          return AVERROR_INVALIDDATA;
  
      /* read vectors and build frame */
      for (y = 0; y < s->avctx->height / 4; y++)
          for (x = 0; x < s->avctx->width / 4; x++) {
              unsigned int vector = get_bits(&gb, vector_bits);
              const uint8_t *src;
              int src_stride;
  
              if (vector < num_mvs) {
                  int mx = x * 4 + s->mv_codebook[vector][0];
                  int my = y * 4 + s->mv_codebook[vector][1];
  
                  if (mx < 0 || mx + 4 > s->avctx->width ||
                      my < 0 || my + 4 > s->avctx->height) {
                      av_log(s->avctx, AV_LOG_ERROR, "MV %d %d out of picture\n", mx, my);
                      continue;
                  }
  
                  src = s->last_frame.data[0] + mx + my * s->last_frame.linesize[0];
                  src_stride = s->last_frame.linesize[0];
              } else {
                  int offset = vector - num_mvs;
                  if (offset < num_blocks_raw)
                      src = blocks_raw + 16*offset;
                  else if (offset - num_blocks_raw < num_blocks_packed)
                      src = s->block_codebook[offset - num_blocks_raw];
                  else
                      continue;
                  src_stride = 4;
              }
  
              for (j = 0; j < 4; j++)
                  for (i = 0; i < 4; i++)
                      frame->data[0][(y * 4 + j) * frame->linesize[0] + (x * 4 + i)] =
                          src[j * src_stride + i];
      }
  
      return 0;
  }
  
  static int tgv_decode_frame(AVCodecContext *avctx,
                              void *data, int *got_frame,
                              AVPacket *avpkt)
  {
      const uint8_t *buf     = avpkt->data;
      int buf_size           = avpkt->size;
      TgvContext *s          = avctx->priv_data;
      const uint8_t *buf_end = buf + buf_size;
      AVFrame *frame         = data;
      int chunk_type, ret;
  
      if (buf_end - buf < EA_PREAMBLE_SIZE)
          return AVERROR_INVALIDDATA;
  
      chunk_type = AV_RL32(&buf[0]);
      buf       += EA_PREAMBLE_SIZE;
  
      if (chunk_type == kVGT_TAG) {
          int pal_count, i;
          if(buf_end - buf < 12) {
              av_log(avctx, AV_LOG_WARNING, "truncated header\n");
              return AVERROR_INVALIDDATA;
          }
  
          s->width  = AV_RL16(&buf[0]);
          s->height = AV_RL16(&buf[2]);
          if (s->avctx->width != s->width || s->avctx->height != s->height) {
              avcodec_set_dimensions(s->avctx, s->width, s->height);
              av_freep(&s->frame_buffer);
              av_frame_unref(&s->last_frame);
          }
  
          pal_count = AV_RL16(&buf[6]);
          buf += 12;
          for(i = 0; i < pal_count && i < AVPALETTE_COUNT && buf_end - buf >= 3; i++) {
              s->palette[i] = 0xFFU << 24 | AV_RB24(buf);
              buf += 3;
          }
      }
  
      if ((ret = av_image_check_size(s->width, s->height, 0, avctx)) < 0)
          return ret;
  
      if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)
          return ret;
  
      memcpy(frame->data[1], s->palette, AVPALETTE_SIZE);
  
      if (chunk_type == kVGT_TAG) {
          int y;
          frame->key_frame = 1;
          frame->pict_type = AV_PICTURE_TYPE_I;
  
          if (!s->frame_buffer &&
              !(s->frame_buffer = av_malloc(s->width * s->height)))
              return AVERROR(ENOMEM);
  
          if (unpack(buf, buf_end, s->frame_buffer, s->avctx->width, s->avctx->height) < 0) {
              av_log(avctx, AV_LOG_WARNING, "truncated intra frame\n");
              return AVERROR_INVALIDDATA;
          }
          for (y = 0; y < s->height; y++)
              memcpy(frame->data[0]  + y * frame->linesize[0],
                     s->frame_buffer + y * s->width,
                     s->width);
      } else {
          if (!s->last_frame.data[0]) {
              av_log(avctx, AV_LOG_WARNING, "inter frame without corresponding intra frame\n");
              return buf_size;
          }
          frame->key_frame = 0;
          frame->pict_type = AV_PICTURE_TYPE_P;
          if (tgv_decode_inter(s, frame, buf, buf_end) < 0) {
              av_log(avctx, AV_LOG_WARNING, "truncated inter frame\n");
              return AVERROR_INVALIDDATA;
          }
      }
  
      av_frame_unref(&s->last_frame);
      if ((ret = av_frame_ref(&s->last_frame, frame)) < 0)
          return ret;
  
      *got_frame = 1;
  
      return buf_size;
  }
  
  static av_cold int tgv_decode_end(AVCodecContext *avctx)
  {
      TgvContext *s = avctx->priv_data;
      av_frame_unref(&s->last_frame);
      av_freep(&s->frame_buffer);
      av_free(s->mv_codebook);
      av_free(s->block_codebook);
      return 0;
  }
  
  AVCodec ff_eatgv_decoder = {
      .name           = "eatgv",
      .type           = AVMEDIA_TYPE_VIDEO,
      .id             = AV_CODEC_ID_TGV,
      .priv_data_size = sizeof(TgvContext),
      .init           = tgv_decode_init,
      .close          = tgv_decode_end,
      .decode         = tgv_decode_frame,
      .long_name      = NULL_IF_CONFIG_SMALL("Electronic Arts TGV video"),
      .capabilities   = CODEC_CAP_DR1,
  };
  