avs_decode_frame(AVCodecContext * avctx, void *data, int *data_size, AVPacket *avpkt) { const uint8_t *buf = avpkt->data; const uint8_t *buf_end = avpkt->data + avpkt->size; int buf_size = avpkt->size; AvsContext *const avs = avctx->priv_data; AVFrame *picture = data; AVFrame *const p = &avs->picture; const uint8_t *table, *vect; uint8_t *out; int i, j, x, y, stride, vect_w = 3, vect_h = 3; AvsVideoSubType sub_type; AvsBlockType type; GetBitContext change_map; if (avctx->reget_buffer(avctx, p)) { av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n"); return -1; } p->reference = 3; p->pict_type = AV_PICTURE_TYPE_P; p->key_frame = 0; out = avs->picture.data[0]; stride = avs->picture.linesize[0]; if (buf_end - buf < 4) return AVERROR_INVALIDDATA; sub_type = buf[0]; type = buf[1]; buf += 4; if (type == AVS_PALETTE) { int first, last; uint32_t *pal = (uint32_t *) avs->picture.data[1]; first = AV_RL16(buf); last = first + AV_RL16(buf + 2); if (first >= 256 || last > 256 || buf_end - buf < 4 + 4 + 3 * (last - first)) return AVERROR_INVALIDDATA; buf += 4; for (i=first; i<last; i++, buf+=3) { pal[i] = (buf[0] << 18) | (buf[1] << 10) | (buf[2] << 2); pal[i] |= 0xFF << 24 | (pal[i] >> 6) & 0x30303; } sub_type = buf[0]; type = buf[1]; buf += 4; } if (type != AVS_VIDEO) return -1; switch (sub_type) { case AVS_I_FRAME: p->pict_type = AV_PICTURE_TYPE_I; p->key_frame = 1; case AVS_P_FRAME_3X3: vect_w = 3; vect_h = 3; break; case AVS_P_FRAME_2X2: vect_w = 2; vect_h = 2; break; case AVS_P_FRAME_2X3: vect_w = 2; vect_h = 3; break; default: return -1; } if (buf_end - buf < 256 * vect_w * vect_h) return AVERROR_INVALIDDATA; table = buf + (256 * vect_w * vect_h); if (sub_type != AVS_I_FRAME) { int map_size = ((318 / vect_w + 7) / 8) * (198 / vect_h); if (buf_end - table < map_size) return AVERROR_INVALIDDATA; init_get_bits(&change_map, table, map_size * 8); table += map_size; } for (y=0; y<198; y+=vect_h) { for (x=0; x<318; x+=vect_w) { if (sub_type == AVS_I_FRAME || get_bits1(&change_map)) { if (buf_end - table < 1) return AVERROR_INVALIDDATA; vect = &buf[*table++ * (vect_w * vect_h)]; for (j=0; j<vect_w; j++) { out[(y + 0) * stride + x + j] = vect[(0 * vect_w) + j]; out[(y + 1) * stride + x + j] = vect[(1 * vect_w) + j]; if (vect_h == 3) out[(y + 2) * stride + x + j] = vect[(2 * vect_w) + j]; } } } if (sub_type != AVS_I_FRAME) align_get_bits(&change_map); } *picture = avs->picture; *data_size = sizeof(AVPicture); return buf_size; }