On 19 Apr 2025, at 16:27, Dimitry Andric <dimi...@unified-streaming.com> wrote:
>
> On 10 Apr 2025, at 11:03, Dimitry Andric <dimi...@unified-streaming.com>
> wrote:
>>
>> On 3 Apr 2025, at 22:02, Dimitry Andric <dimi...@unified-streaming.com>
>> wrote:
>>>
>>> When decoding fragmented MP4 files that have an empty stsc box, and
>>> instead contain sample description indexes in their tfhd boxes, the mov
>>> demuxer does not notify the decoder whenever the current sample
>>> description index changes. If the SPS or PPS changed sufficiently, this
>>> can lead to unexpected decoding errors.
>>>
>>> To fix this, in mov_finalize_packet(), when stsc_data is not available,
>>> use get_frag_stream_info_from_pkt() to get at the current fragment
>>> stream info, and retrieve the current sample description index from
>>> there. Then use that index in a similar manner as the stsc case.
>>>
>>> Signed-off-by: Dimitry Andric <dimi...@unified-streaming.com>
>>> ---
>>> libavformat/mov.c | 50 ++++++++++++++++++++++++++++-------------------
>>> 1 file changed, 30 insertions(+), 20 deletions(-)
>>>
>>> diff --git a/libavformat/mov.c b/libavformat/mov.c
>>> index 452690090c..ead89192f4 100644
>>> --- a/libavformat/mov.c
>>> +++ b/libavformat/mov.c
>>> @@ -10756,25 +10756,29 @@ static int mov_switch_root(AVFormatContext *s,
>>> int64_t target, int index)
>>> return 1;
>>> }
>>>
>>> -static int mov_change_extradata(AVStream *st, AVPacket *pkt)
>>> +static int mov_change_extradata(AVStream *st, AVPacket *pkt, int stsd_id)
>>> {
>>> MOVStreamContext *sc = st->priv_data;
>>> uint8_t *side, *extradata;
>>> int extradata_size;
>>>
>>> - /* Save the current index. */
>>> - sc->last_stsd_index = sc->stsc_data[sc->stsc_index].id - 1;
>>> + if (stsd_id > 0 &&
>>> + stsd_id - 1 < sc->stsd_count &&
>>> + stsd_id - 1 != sc->last_stsd_index) {
>>> + /* Save the current index. */
>>> + sc->last_stsd_index = stsd_id - 1;
>>>
>>> - /* Notify the decoder that extradata changed. */
>>> - extradata_size = sc->extradata_size[sc->last_stsd_index];
>>> - extradata = sc->extradata[sc->last_stsd_index];
>>> - if (st->discard != AVDISCARD_ALL && extradata_size > 0 && extradata) {
>>> - side = av_packet_new_side_data(pkt,
>>> - AV_PKT_DATA_NEW_EXTRADATA,
>>> - extradata_size);
>>> - if (!side)
>>> - return AVERROR(ENOMEM);
>>> - memcpy(side, extradata, extradata_size);
>>> + /* Notify the decoder that extradata changed. */
>>> + extradata_size = sc->extradata_size[sc->last_stsd_index];
>>> + extradata = sc->extradata[sc->last_stsd_index];
>>> + if (st->discard != AVDISCARD_ALL && extradata_size > 0 &&
>>> extradata) {
>>> + side = av_packet_new_side_data(pkt,
>>> + AV_PKT_DATA_NEW_EXTRADATA,
>>> + extradata_size);
>>> + if (!side)
>>> + return AVERROR(ENOMEM);
>>> + memcpy(side, extradata, extradata_size);
>>> + }
>>> }
>>>
>>> return 0;
>>> @@ -10893,13 +10897,10 @@ static int mov_finalize_packet(AVFormatContext
>>> *s, AVStream *st, AVIndexEntry *s
>>>
>>> /* Multiple stsd handling. */
>>> if (sc->stsc_data) {
>>> - if (sc->stsc_data[sc->stsc_index].id > 0 &&
>>> - sc->stsc_data[sc->stsc_index].id - 1 < sc->stsd_count &&
>>> - sc->stsc_data[sc->stsc_index].id - 1 != sc->last_stsd_index) {
>>> - int ret = mov_change_extradata(st, pkt);
>>> - if (ret < 0)
>>> - return ret;
>>> - }
>>> + int stsd_id = sc->stsc_data[sc->stsc_index].id;
>>> + int ret = mov_change_extradata(st, pkt, stsd_id);
>>> + if (ret < 0)
>>> + return ret;
>>>
>>> /* Update the stsc index for the next sample */
>>> sc->stsc_sample++;
>>> @@ -10908,6 +10909,15 @@ static int mov_finalize_packet(AVFormatContext *s,
>>> AVStream *st, AVIndexEntry *s
>>> sc->stsc_index++;
>>> sc->stsc_sample = 0;
>>> }
>>> + } else {
>>> + MOVContext *mov = s->priv_data;
>>> + MOVFragmentStreamInfo *frag_stream_info =
>>> get_frag_stream_info_from_pkt(&mov->frag_index, pkt, sc->id);
>>> + if (frag_stream_info) {
>>> + int stsd_id = frag_stream_info->stsd_id;
>>> + int ret = mov_change_extradata(st, pkt, stsd_id);
>>> + if (ret < 0)
>>> + return ret;
>>> + }
>>> }
>>>
>>> return 0;
>>> --
>>> 2.43.0
>>>
>>
>> Any comments on this patch?
>
> Ping :)
Is there any particular group of persons that "own" the mov muxer?
-Dimitry
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
To unsubscribe, visit link above, or email
ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
