static int h264_mp4toannexb_filter(AVBitStreamFilterContext *bsfc, AVCodecContext *avctx, const char *args, uint8_t **poutbuf, int *poutbuf_size, const uint8_t *buf, int buf_size, int keyframe) { H264BSFContext *ctx = bsfc->priv_data; int i; uint8_t unit_type; int32_t nal_size; uint32_t cumul_size = 0; const uint8_t *buf_end = buf + buf_size; int ret = 0; /* nothing to filter */ if (!avctx->extradata || avctx->extradata_size < 6) { *poutbuf = (uint8_t *)buf; *poutbuf_size = buf_size; return 0; } /* retrieve sps and pps NAL units from extradata */ if (!ctx->extradata_parsed) { if (args && strstr(args, "private_spspps_buf")) ctx->private_spspps = 1; ret = h264_extradata_to_annexb(ctx, avctx, AV_INPUT_BUFFER_PADDING_SIZE); if (ret < 0) return ret; ctx->length_size = ret; ctx->new_idr = 1; ctx->idr_sps_seen = 0; ctx->idr_pps_seen = 0; ctx->extradata_parsed = 1; } *poutbuf_size = 0; *poutbuf = NULL; do { ret= AVERROR(EINVAL); if (buf + ctx->length_size > buf_end) goto fail; for (nal_size = 0, i = 0; i<ctx->length_size; i++) nal_size = (nal_size << 8) | buf[i]; buf += ctx->length_size; unit_type = *buf & 0x1f; if (buf + nal_size > buf_end || nal_size < 0) goto fail; if (unit_type == 7) ctx->idr_sps_seen = ctx->new_idr = 1; else if (unit_type == 8) { ctx->idr_pps_seen = ctx->new_idr = 1; /* if SPS has not been seen yet, prepend the AVCC one to PPS */ if (!ctx->idr_sps_seen) { if (ctx->sps_offset == -1) av_log(avctx, AV_LOG_WARNING, "SPS not present in the stream, nor in AVCC, stream may be unreadable\n"); else { if ((ret = alloc_and_copy(poutbuf, poutbuf_size, ctx->spspps_buf + ctx->sps_offset, ctx->pps_offset != -1 ? ctx->pps_offset : ctx->spspps_size - ctx->sps_offset, buf, nal_size)) < 0) goto fail; ctx->idr_sps_seen = 1; goto next_nal; } } } /* if this is a new IDR picture following an IDR picture, reset the idr flag. * Just check first_mb_in_slice to be 0 as this is the simplest solution. * This could be checking idr_pic_id instead, but would complexify the parsing. */ if (!ctx->new_idr && unit_type == 5 && (buf[1] & 0x80)) ctx->new_idr = 1; /* prepend only to the first type 5 NAL unit of an IDR picture, if no sps/pps are already present */ if (ctx->new_idr && unit_type == 5 && !ctx->idr_sps_seen && !ctx->idr_pps_seen) { if ((ret=alloc_and_copy(poutbuf, poutbuf_size, ctx->spspps_buf, ctx->spspps_size, buf, nal_size)) < 0) goto fail; ctx->new_idr = 0; /* if only SPS has been seen, also insert PPS */ } else if (ctx->new_idr && unit_type == 5 && ctx->idr_sps_seen && !ctx->idr_pps_seen) { if (ctx->pps_offset == -1) { av_log(avctx, AV_LOG_WARNING, "PPS not present in the stream, nor in AVCC, stream may be unreadable\n"); if ((ret = alloc_and_copy(poutbuf, poutbuf_size, NULL, 0, buf, nal_size)) < 0) goto fail; } else if ((ret = alloc_and_copy(poutbuf, poutbuf_size, ctx->spspps_buf + ctx->pps_offset, ctx->spspps_size - ctx->pps_offset, buf, nal_size)) < 0) goto fail; } else { if ((ret=alloc_and_copy(poutbuf, poutbuf_size, NULL, 0, buf, nal_size)) < 0) goto fail; if (!ctx->new_idr && unit_type == 1) { ctx->new_idr = 1; ctx->idr_sps_seen = 0; ctx->idr_pps_seen = 0; } } next_nal: buf += nal_size; cumul_size += nal_size + ctx->length_size; } while (cumul_size < buf_size); return 1; fail: av_freep(poutbuf); *poutbuf_size = 0; return ret; }