[FFmpeg-devel] [PATCH] avcodec/bsf/h264_mp4toannexb.c: change extradata to annexb if this is avcc.

[Zhao Zhili]

> On Apr 24, 2025, at 20:42, jiangjie <jiangjie618 at gmail.com> wrote:
> 
> if get AV_PKT_DATA_NEW_EXTRADATA in AVPacket, this bitstream filter will return an error.
> ffmpeg -i rtmp://xxx/live/xxx -bsf:v "h264_mp4toannexb,h264_metadata=aud=remove" -c copy -f null -

The subject and commit message is confusing.

’this’ isn’t a bitstream filter, it’s a bsf chain. And what report error is h264_metadata, not h264_mp4toannexb.

The subject can be: Remove NEW_EXTRADATA sidedata

And commit message can be:

We don’t support mixed bitstream format. For example, h264_metadata report error in this case


> ---
> libavcodec/bsf/h264_mp4toannexb.c             | 26 ++++++++++++++-----
> tests/fate/h264.mak                           |  3 +++
> .../fate/h264-bsf-mp4toannexb-h264_metadata   | 12 +++++++++
> 3 files changed, 35 insertions(+), 6 deletions(-)
> create mode 100644 tests/ref/fate/h264-bsf-mp4toannexb-h264_metadata
> 
> diff --git a/libavcodec/bsf/h264_mp4toannexb.c b/libavcodec/bsf/h264_mp4toannexb.c
> index dda064287e..42a5a274bf 100644
> --- a/libavcodec/bsf/h264_mp4toannexb.c
> +++ b/libavcodec/bsf/h264_mp4toannexb.c
> @@ -252,14 +252,21 @@ static int h264_mp4toannexb_filter_ps(H264BSFContext *s,
>     return 0;
> }
> 
> +static int is_annexb(const uint8_t *extradata, int extra_size) {
> +    if (!extra_size || (extra_size >= 3 && AV_RB24(extradata) == 1) ||
> +        (extra_size >= 4 && AV_RB32(extradata) == 1)) {
> +        return 1;
> +    } else {
> +        return 0;
> +    }
> +}
> +
> static int h264_mp4toannexb_init(AVBSFContext *ctx)
> {
>     int extra_size = ctx->par_in->extradata_size;
> 
>     /* retrieve sps and pps NAL units from extradata */
> -    if (!extra_size                                               ||
> -        (extra_size >= 3 && AV_RB24(ctx->par_in->extradata) == 1) ||
> -        (extra_size >= 4 && AV_RB32(ctx->par_in->extradata) == 1)) {
> +    if (is_annexb(ctx->par_in->extradata, extra_size)) {
>         av_log(ctx, AV_LOG_VERBOSE,
>                "The input looks like it is Annex B already\n");
>     } else if (extra_size >= 7) {
> @@ -294,9 +301,16 @@ static int h264_mp4toannexb_filter(AVBSFContext *ctx, AVPacket *opkt)
>     extradata = av_packet_get_side_data(in, AV_PKT_DATA_NEW_EXTRADATA,
>                                         &extradata_size);
>     if (extradata) {
> -        ret = h264_extradata_to_annexb(ctx, extradata, extradata_size);
> -        if (ret < 0)
> -            goto fail;
> +        if (!is_annexb(extradata, extradata_size) && extradata_size >= 7) {
> +            ret = h264_extradata_to_annexb(ctx, extradata, extradata_size);
> +            if (ret < 0)
> +                goto fail;
> +            av_packet_side_data_remove(in->side_data, &in->side_data_elems,
> +                                       AV_PKT_DATA_NEW_EXTRADATA);
> +            uint8_t *data = av_packet_new_side_data(
> +                in, AV_PKT_DATA_NEW_EXTRADATA, ctx->par_out->extradata_size);
> +            memcpy(data, ctx->par_out->extradata, ctx->par_out->extradata_size);
> +        }

Remove adding AV_PKT_DATA_NEW_EXTRADATA. There’re in-band PS now.

There is another case which not belonging to this patch. With AV_PKT_DATA_NEW_EXTRADATA
in annexb format, it should be inserted as in-band PS and also be removed after. 

>     }
> 
>     /* nothing to filter */
> diff --git a/tests/fate/h264.mak b/tests/fate/h264.mak
> index 00b153cc93..7b3e865955 100644
> --- a/tests/fate/h264.mak
> +++ b/tests/fate/h264.mak
> @@ -231,6 +231,7 @@ FATE_H264-$(call DEMMUX, MOV, H264, H264_MP4TOANNEXB_BSF) += fate-h264-bsf-mp4to
>                                                              fate-h264-bsf-mp4toannexb-2 \
>                                                              fate-h264_mp4toannexb_ticket5927 \
>                                                              fate-h264_mp4toannexb_ticket5927_2 \
> +                                                             fate-h264-bsf-mp4toannexb-h264_metadata \
> 
> FATE_H264-$(call DEMMUX, H264, MOV, DTS2PTS_BSF) += fate-h264-bsf-dts2pts
> 
> @@ -441,6 +442,8 @@ fate-h264-bsf-mp4toannexb-2:                      CMD = md5 -i $(TARGET_SAMPLES)
> fate-h264-bsf-mp4toannexb-2:                      CMP = oneline
> fate-h264-bsf-mp4toannexb-2:                      REF = cffcfa6a2d0b58c9de1f5785f099f41d
> fate-h264-bsf-mp4toannexb-new-extradata:          CMD = stream_remux mov $(TARGET_SAMPLES)/h264/extradata-reload-multi-stsd.mov "" h264 "-map 0:v"
> +fate-h264-bsf-mp4toannexb-h264_metadata:          CMD = transcode mov $(TARGET_SAMPLES)/h264/extradata-reload-multi-stsd.mov \
> +                                                        h264 "-c:v copy -bsf:v h264_mp4toannexb,h264_metadata=aud=remove" "-c:v copy"
> fate-h264-bsf-dts2pts:                            CMD = transcode "h264" $(TARGET_SAMPLES)/h264-conformance/CAPAMA3_Sand_F.264 \
>                                                         mov "-c:v copy -bsf:v dts2pts -frames:v 50" "-c:v copy"
> fate-h264_mp4toannexb_ticket5927:                 CMD = transcode "mp4" $(TARGET_SAMPLES)/h264/thezerotheorem-cut.mp4 \
> diff --git a/tests/ref/fate/h264-bsf-mp4toannexb-h264_metadata b/tests/ref/fate/h264-bsf-mp4toannexb-h264_metadata
> new file mode 100644
> index 0000000000..d3ba7f1886
> --- /dev/null
> +++ b/tests/ref/fate/h264-bsf-mp4toannexb-h264_metadata
> @@ -0,0 +1,12 @@
> +a48f175bf3458410d1dd1907682b92d3 *tests/data/fate/h264-bsf-mp4toannexb-h264_metadata.h264
> +4642 tests/data/fate/h264-bsf-mp4toannexb-h264_metadata.h264
> +#extradata 0:       38, 0x84d70914
> +#tb 0: 1/1200000
> +#media_type 0: video
> +#codec_id 0: h264
> +#dimensions 0: 256x128
> +#sar 0: 1/1
> +0,     -96000, -9223372036854775808,    48000,     2331, 0xc97509cb
> +0,     -48000, -9223372036854775808,    48000,       64, 0x6ad91f4e, F=0x0
> +0,          0, -9223372036854775808,    48000,     2203, 0xe376d2a9
> +0,      48000, -9223372036854775808,    48000,       44, 0x687a10ea, F=0x0
> -- 
> 2.49.0