[FFmpeg-devel] [PATCH] avformat/pcmdec: add pts and dts calculation for pcmdec
Andreas Rheinhardt
andreas.rheinhardt at outlook.com
Wed May 15 04:39:44 EEST 2024
Hiccup Zhu:
> The purpose of this patch is to calculate pts and dts when using pcmdemux.
> Is there anything wrong with doing this, or do you have any suggestions for
> improvement?
>
1. Don't top-post on this list.
2. PTS and DTS are already produced with this demuxer. As has been said:
If it isn't for you, open a ticket about it.
> Andreas Rheinhardt <andreas.rheinhardt at outlook.com> 于2024年5月14日周二 19:41写道:
>
>> Shiqi Zhu:
>>> Signed-off-by: Shiqi Zhu <hiccupzhu at gmail.com>
>>> ---
>>> libavformat/pcmdec.c | 37 +++++++++++++++++++++++++++++++++++--
>>> 1 file changed, 35 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/libavformat/pcmdec.c b/libavformat/pcmdec.c
>>> index 2f6508b75a..d879aefaad 100644
>>> --- a/libavformat/pcmdec.c
>>> +++ b/libavformat/pcmdec.c
>>> @@ -36,6 +36,7 @@ typedef struct PCMAudioDemuxerContext {
>>> AVClass *class;
>>> int sample_rate;
>>> AVChannelLayout ch_layout;
>>> + int64_t nb_samples;
>>> } PCMAudioDemuxerContext;
>>>
>>> static int pcm_read_header(AVFormatContext *s)
>>> @@ -46,6 +47,7 @@ static int pcm_read_header(AVFormatContext *s)
>>> uint8_t *mime_type = NULL;
>>> int ret;
>>>
>>> + s1->nb_samples = 0;
>>> st = avformat_new_stream(s, NULL);
>>> if (!st)
>>> return AVERROR(ENOMEM);
>>> @@ -104,6 +106,37 @@ static int pcm_read_header(AVFormatContext *s)
>>> return 0;
>>> }
>>>
>>> +static int pcm_dec_read_packet(AVFormatContext *s, AVPacket *pkt)
>>> +{
>>> + PCMAudioDemuxerContext *s1 = s->priv_data;
>>> + AVCodecParameters *par = s->streams[0]->codecpar;
>>> + int ret;
>>> +
>>> + ret = ff_pcm_read_packet(s, pkt);
>>> + if (ret < 0)
>>> + return ret;
>>> +
>>> + pkt->time_base = s->streams[0]->time_base;
>>> + pkt->dts = pkt->pts = s1->nb_samples;
>>> + s1->nb_samples += pkt->size / par->block_align;
>>> +
>>> + return ret;
>>> +}
>>> +
>>> +static int pcm_dec_read_seek(AVFormatContext *s,
>>> + int stream_index, int64_t timestamp, int
>> flags)
>>> +{
>>> + PCMAudioDemuxerContext *s1 = s->priv_data;
>>> + int ret;
>>> +
>>> + ret = ff_pcm_read_seek(s, stream_index, timestamp, flags);
>>> + if (ret < 0)
>>> + return ret;
>>> +
>>> + s1->nb_samples = ffstream(s->streams[0])->cur_dts;
>>> + return ret;
>>> +}
>>> +
>>> static const AVOption pcm_options[] = {
>>> { "sample_rate", "", offsetof(PCMAudioDemuxerContext, sample_rate),
>> AV_OPT_TYPE_INT, {.i64 = 44100}, 0, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
>>> { "ch_layout", "", offsetof(PCMAudioDemuxerContext, ch_layout),
>> AV_OPT_TYPE_CHLAYOUT, {.str = "mono"}, 0, 0, AV_OPT_FLAG_DECODING_PARAM },
>>> @@ -126,8 +159,8 @@ const FFInputFormat ff_pcm_ ## name_ ## _demuxer =
>> { \
>>> .p.priv_class = &pcm_demuxer_class, \
>>> .priv_data_size = sizeof(PCMAudioDemuxerContext), \
>>> .read_header = pcm_read_header, \
>>> - .read_packet = ff_pcm_read_packet, \
>>> - .read_seek = ff_pcm_read_seek, \
>>> + .read_packet = pcm_dec_read_packet, \
>>> + .read_seek = pcm_dec_read_seek, \
>>> .raw_codec_id = codec, \
>>> __VA_ARGS__ \
>>> };
>>
>> A quick test shows that PTS and DTS are already set generically for pcm
>> formats (unless the AVFMT_FLAG_NOFILLIN flag is set). If it is not in
>> your usecase, then you should provide details about this (preferably by
>> opening a ticket on trac).
>>
>> - Andreas
>>
>> _______________________________________________
>> ffmpeg-devel mailing list
>> ffmpeg-devel at ffmpeg.org
>> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>>
>> To unsubscribe, visit link above, or email
>> ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".
>>
>
>
More information about the ffmpeg-devel
mailing list