static int gif_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt) { GifState *s = avctx->priv_data; AVFrame *picture = data; int ret; bytestream2_init(&s->gb, avpkt->data, avpkt->size); s->picture.pts = avpkt->pts; s->picture.pkt_pts = avpkt->pts; s->picture.pkt_dts = avpkt->dts; s->picture.pkt_duration = avpkt->duration; if (avpkt->size >= 6) { s->keyframe = memcmp(avpkt->data, gif87a_sig, 6) == 0 || memcmp(avpkt->data, gif89a_sig, 6) == 0; } else { s->keyframe = 0; if (s->keyframe) { s->keyframe_ok = 0; if ((ret = gif_read_header1(s)) < 0) return ret; if ((ret = av_image_check_size(s->screen_width, s->screen_height, 0, avctx)) < 0) return ret; avcodec_set_dimensions(avctx, s->screen_width, s->screen_height); if (s->picture.data[0]) avctx->release_buffer(avctx, &s->picture); if ((ret = ff_get_buffer(avctx, &s->picture)) < 0) { av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); return ret; s->picture.pict_type = AV_PICTURE_TYPE_I; s->picture.key_frame = 1; } else { if ((ret = avctx->reget_buffer(avctx, &s->picture)) < 0) { av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n"); return ret; s->picture.pict_type = AV_PICTURE_TYPE_P; s->picture.key_frame = 0; ret = gif_parse_next_image(s, got_frame); if (ret < 0) return ret; else if (*got_frame) *picture = s->picture; return avpkt->size;