static int svq1_decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt) { const uint8_t *buf = avpkt->data; int buf_size = avpkt->size; MpegEncContext *s=avctx->priv_data; uint8_t *current, *previous; int result, i, x, y, width, height; AVFrame *pict = data; svq1_pmv *pmv; /* initialize bit buffer */ init_get_bits(&s->gb,buf,buf_size*8); /* decode frame header */ s->f_code = get_bits (&s->gb, 22); if ((s->f_code & ~0x70) || !(s->f_code & 0x60)) return -1; /* swap some header bytes (why?) */ if (s->f_code != 0x20) { uint32_t *src = (uint32_t *) (buf + 4); for (i=0; i < 4; i++) { src[i] = ((src[i] << 16) | (src[i] >> 16)) ^ src[7 - i]; } } result = svq1_decode_frame_header (&s->gb, s); if (result != 0) { av_dlog(s->avctx, "Error in svq1_decode_frame_header %i\n",result); return result; } avcodec_set_dimensions(avctx, s->width, s->height); //FIXME this avoids some confusion for "B frames" without 2 references //this should be removed after libavcodec can handle more flexible picture types & ordering if(s->pict_type==AV_PICTURE_TYPE_B && s->last_picture_ptr==NULL) return buf_size; if( (avctx->skip_frame >= AVDISCARD_NONREF && s->pict_type==AV_PICTURE_TYPE_B) ||(avctx->skip_frame >= AVDISCARD_NONKEY && s->pict_type!=AV_PICTURE_TYPE_I) || avctx->skip_frame >= AVDISCARD_ALL) return buf_size; if(ff_MPV_frame_start(s, avctx) < 0) return -1; pmv = av_malloc((FFALIGN(s->width, 16)/8 + 3) * sizeof(*pmv)); if (!pmv) return -1; /* decode y, u and v components */ for (i=0; i < 3; i++) { int linesize; if (i == 0) { width = FFALIGN(s->width, 16); height = FFALIGN(s->height, 16); linesize= s->linesize; } else { if(s->flags&CODEC_FLAG_GRAY) break; width = FFALIGN(s->width/4, 16); height = FFALIGN(s->height/4, 16); linesize= s->uvlinesize; } current = s->current_picture.f.data[i]; if(s->pict_type==AV_PICTURE_TYPE_B){ previous = s->next_picture.f.data[i]; }else{ previous = s->last_picture.f.data[i]; } if (s->pict_type == AV_PICTURE_TYPE_I) { /* keyframe */ for (y=0; y < height; y+=16) { for (x=0; x < width; x+=16) { result = svq1_decode_block_intra (&s->gb, &current[x], linesize); if (result != 0) { av_log(s->avctx, AV_LOG_ERROR, "Error in svq1_decode_block %i (keyframe)\n",result); goto err; } } current += 16*linesize; } } else { /* delta frame */ memset (pmv, 0, ((width / 8) + 3) * sizeof(svq1_pmv)); for (y=0; y < height; y+=16) { for (x=0; x < width; x+=16) { result = svq1_decode_delta_block (s, &s->gb, &current[x], previous, linesize, pmv, x, y); if (result != 0) { av_dlog(s->avctx, "Error in svq1_decode_delta_block %i\n",result); goto err; } } pmv[0].x = pmv[0].y = 0; current += 16*linesize; } } } *pict = s->current_picture.f; ff_MPV_frame_end(s); *data_size=sizeof(AVFrame); result = buf_size; err: av_free(pmv); return result; }