[FFmpeg-devel] [PATCH v5 1/2] avformat: refactor ff_stream_encode_params_copy() to ff_stream_params_copy()

Andreas Rheinhardt andreas.rheinhardt at outlook.com
Fri Aug 5 01:22:04 EEST 2022


Pierre-Anthony Lemieux:
> On Thu, Aug 4, 2022 at 10:15 AM Andreas Rheinhardt
> <andreas.rheinhardt at outlook.com> wrote:
>>
>> Pierre-Anthony Lemieux:
>>> On Thu, Aug 4, 2022 at 9:53 AM Andreas Rheinhardt
>>> <andreas.rheinhardt at outlook.com> wrote:
>>>>
>>>> pal at sandflow.com:
>>>>> From: Pierre-Anthony Lemieux <pal at palemieux.com>
>>>>>
>>>>> As discussed at https://ffmpeg.org/pipermail/ffmpeg-devel/2022-July/298491.html.
>>>>> Note that ff_stream_params_copy() does not copy:
>>>>>  * the index field
>>>>>  * the attached_pic if its size is 0
>>>>>
>>>>> Addresses http://ffmpeg.org/pipermail/ffmpeg-devel/2022-August/299514.html
>>>>>
>>>>> ---
>>>>>  libavformat/avformat.c   | 40 ++++++++++++++++++++++++++++++++++++++++
>>>>>  libavformat/fifo.c       |  2 +-
>>>>>  libavformat/internal.h   | 12 ++++++++++++
>>>>>  libavformat/mux.h        |  9 ---------
>>>>>  libavformat/mux_utils.c  | 28 ----------------------------
>>>>>  libavformat/segment.c    |  2 +-
>>>>>  libavformat/tee.c        |  2 +-
>>>>>  libavformat/webm_chunk.c |  2 +-
>>>>>  8 files changed, 56 insertions(+), 41 deletions(-)
>>>>>
>>>>> diff --git a/libavformat/avformat.c b/libavformat/avformat.c
>>>>> index 30d6ea6a49..242187c359 100644
>>>>> --- a/libavformat/avformat.c
>>>>> +++ b/libavformat/avformat.c
>>>>> @@ -235,6 +235,46 @@ int ff_stream_side_data_copy(AVStream *dst, const AVStream *src)
>>>>>      return 0;
>>>>>  }
>>>>>
>>>>> +int ff_stream_params_copy(AVStream *dst, const AVStream *src)
>>>>> +{
>>>>> +    int ret;
>>>>> +
>>>>> +    dst->id                  = src->id;
>>>>> +    dst->time_base           = src->time_base;
>>>>> +    dst->start_time          = src->start_time;
>>>>> +    dst->duration            = src->duration;
>>>>> +    dst->nb_frames           = src->nb_frames;
>>>>> +    dst->disposition         = src->disposition;
>>>>> +    dst->discard             = src->discard;
>>>>> +    dst->sample_aspect_ratio = src->sample_aspect_ratio;
>>>>> +    dst->avg_frame_rate      = src->avg_frame_rate;
>>>>> +    dst->event_flags         = src->event_flags;
>>>>> +    dst->r_frame_rate        = src->r_frame_rate;
>>>>> +    dst->pts_wrap_bits       = src->pts_wrap_bits;
>>>>> +
>>>>> +    av_dict_free(&dst->metadata);
>>>>> +    ret = av_dict_copy(&dst->metadata, src->metadata, 0);
>>>>> +    if (ret < 0)
>>>>> +        return ret;
>>>>> +
>>>>> +    ret = avcodec_parameters_copy(dst->codecpar, src->codecpar);
>>>>> +    if (ret < 0)
>>>>> +        return ret;
>>>>> +
>>>>> +    ret = ff_stream_side_data_copy(dst, src);
>>>>> +    if (ret < 0)
>>>>> +        return ret;
>>>>> +
>>>>> +    av_packet_unref(&dst->attached_pic);
>>>>> +    if (src->attached_pic.size > 0) {
>>>>> +        ret = av_packet_ref(&dst->attached_pic, &src->attached_pic);
>>>>> +        if (ret < 0)
>>>>> +            return ret;
>>>>> +    }
>>>>> +
>>>>> +    return 0;
>>>>> +}
>>>>> +
>>>>>  AVProgram *av_new_program(AVFormatContext *ac, int id)
>>>>>  {
>>>>>      AVProgram *program = NULL;
>>>>> diff --git a/libavformat/fifo.c b/libavformat/fifo.c
>>>>> index ead2bdc5cf..fef116d040 100644
>>>>> --- a/libavformat/fifo.c
>>>>> +++ b/libavformat/fifo.c
>>>>> @@ -509,7 +509,7 @@ static int fifo_mux_init(AVFormatContext *avf, const AVOutputFormat *oformat,
>>>>>          if (!st)
>>>>>              return AVERROR(ENOMEM);
>>>>>
>>>>> -        ret = ff_stream_encode_params_copy(st, avf->streams[i]);
>>>>> +        ret = ff_stream_params_copy(st, avf->streams[i]);
>>>>>          if (ret < 0)
>>>>>              return ret;
>>>>>      }
>>>>> diff --git a/libavformat/internal.h b/libavformat/internal.h
>>>>> index b6b8fbf56f..87a00bbae3 100644
>>>>> --- a/libavformat/internal.h
>>>>> +++ b/libavformat/internal.h
>>>>> @@ -625,6 +625,18 @@ enum AVCodecID ff_get_pcm_codec_id(int bps, int flt, int be, int sflags);
>>>>>   */
>>>>>  int ff_stream_side_data_copy(AVStream *dst, const AVStream *src);
>>>>>
>>>>> +/**
>>>>> + * Copy all stream parameters from source to destination stream, with the
>>>>> + * exception of:
>>>>> + *  * the index field, which is usually set by avformat_new_stream()
>>>>> + *  * the attached_pic field, if attached_pic.size is 0 or less
>>>>> + *
>>>>> + * @param dst pointer to destination AVStream
>>>>> + * @param src pointer to source AVStream
>>>>> + * @return >=0 on success, AVERROR code on error
>>>>> + */
>>>>> +int ff_stream_params_copy(AVStream *dst, const AVStream *src);
>>>>> +
>>>>>  /**
>>>>>   * Wrap ffurl_move() and log if error happens.
>>>>>   *
>>>>> diff --git a/libavformat/mux.h b/libavformat/mux.h
>>>>> index c01da82194..1bfcaf795f 100644
>>>>> --- a/libavformat/mux.h
>>>>> +++ b/libavformat/mux.h
>>>>> @@ -113,15 +113,6 @@ int ff_format_shift_data(AVFormatContext *s, int64_t read_start, int shift_size)
>>>>>   */
>>>>>  int ff_format_output_open(AVFormatContext *s, const char *url, AVDictionary **options);
>>>>>
>>>>> -/**
>>>>> - * Copy encoding parameters from source to destination stream
>>>>> - *
>>>>> - * @param dst pointer to destination AVStream
>>>>> - * @param src pointer to source AVStream
>>>>> - * @return >=0 on success, AVERROR code on error
>>>>> - */
>>>>> -int ff_stream_encode_params_copy(AVStream *dst, const AVStream *src);
>>>>> -
>>>>>  /**
>>>>>   * Parse creation_time in AVFormatContext metadata if exists and warn if the
>>>>>   * parsing fails.
>>>>> diff --git a/libavformat/mux_utils.c b/libavformat/mux_utils.c
>>>>> index eb8ea3d560..2fa2ab5b0f 100644
>>>>> --- a/libavformat/mux_utils.c
>>>>> +++ b/libavformat/mux_utils.c
>>>>> @@ -121,34 +121,6 @@ int ff_format_output_open(AVFormatContext *s, const char *url, AVDictionary **op
>>>>>      return 0;
>>>>>  }
>>>>>
>>>>> -int ff_stream_encode_params_copy(AVStream *dst, const AVStream *src)
>>>>> -{
>>>>> -    int ret;
>>>>> -
>>>>> -    dst->id                  = src->id;
>>>>> -    dst->time_base           = src->time_base;
>>>>> -    dst->nb_frames           = src->nb_frames;
>>>>> -    dst->disposition         = src->disposition;
>>>>> -    dst->sample_aspect_ratio = src->sample_aspect_ratio;
>>>>> -    dst->avg_frame_rate      = src->avg_frame_rate;
>>>>> -    dst->r_frame_rate        = src->r_frame_rate;
>>>>> -
>>>>> -    av_dict_free(&dst->metadata);
>>>>> -    ret = av_dict_copy(&dst->metadata, src->metadata, 0);
>>>>> -    if (ret < 0)
>>>>> -        return ret;
>>>>> -
>>>>> -    ret = avcodec_parameters_copy(dst->codecpar, src->codecpar);
>>>>> -    if (ret < 0)
>>>>> -        return ret;
>>>>> -
>>>>> -    ret = ff_stream_side_data_copy(dst, src);
>>>>> -    if (ret < 0)
>>>>> -        return ret;
>>>>> -
>>>>> -    return 0;
>>>>> -}
>>>>> -
>>>>>  int ff_parse_creation_time_metadata(AVFormatContext *s, int64_t *timestamp, int return_seconds)
>>>>>  {
>>>>>      AVDictionaryEntry *entry;
>>>>> diff --git a/libavformat/segment.c b/libavformat/segment.c
>>>>> index fa435d9f32..a8f3e94714 100644
>>>>> --- a/libavformat/segment.c
>>>>> +++ b/libavformat/segment.c
>>>>> @@ -169,7 +169,7 @@ static int segment_mux_init(AVFormatContext *s)
>>>>>
>>>>>          if (!(st = avformat_new_stream(oc, NULL)))
>>>>>              return AVERROR(ENOMEM);
>>>>> -        ret = ff_stream_encode_params_copy(st, ist);
>>>>> +        ret = ff_stream_params_copy(st, ist);
>>>>>          if (ret < 0)
>>>>>              return ret;
>>>>>          opar = st->codecpar;
>>>>> diff --git a/libavformat/tee.c b/libavformat/tee.c
>>>>> index f1f2a9d2a5..dbfad604d0 100644
>>>>> --- a/libavformat/tee.c
>>>>> +++ b/libavformat/tee.c
>>>>> @@ -289,7 +289,7 @@ static int open_slave(AVFormatContext *avf, char *slave, TeeSlave *tee_slave)
>>>>>              goto end;
>>>>>          }
>>>>>
>>>>> -        ret = ff_stream_encode_params_copy(st2, st);
>>>>> +        ret = ff_stream_params_copy(st2, st);
>>>>>          if (ret < 0)
>>>>>              goto end;
>>>>>      }
>>>>> diff --git a/libavformat/webm_chunk.c b/libavformat/webm_chunk.c
>>>>> index d69db3a004..39f21fce7a 100644
>>>>> --- a/libavformat/webm_chunk.c
>>>>> +++ b/libavformat/webm_chunk.c
>>>>> @@ -94,7 +94,7 @@ static int webm_chunk_init(AVFormatContext *s)
>>>>>      if (!(st = avformat_new_stream(oc, NULL)))
>>>>>          return AVERROR(ENOMEM);
>>>>>
>>>>> -    if ((ret = ff_stream_encode_params_copy(st, ost)) < 0)
>>>>> +    if ((ret = ff_stream_params_copy(st, ost)) < 0)
>>>>>          return ret;
>>>>>
>>>>>      if (wc->http_method)
>>>>
>>>> Looking at these callers shows that they all have one thing in common:
>>>> They create a stream and immediately afterwards copy stream parameters.
>>>> The caller that you intend to add in #2 does the same. How about we make
>>>> a function that is equivalent to
>>>> avformat_new_stream+ff_stream_params_copy above and use that? (But
>>>> please leave ff_stream_params_copy as it is in the form of a static
>>>> function.)
>>>
>>> avformat_clone_stream()?
>>>
>>
>> I was not thinking about a public function. But clone_stream sounds good.
> 
> Something like this?
> 
> int ff_stream_clone(AVFormatContext *s, AVStream **dst, const AVStream *src)
> {
>     AVStream *st;
>     int ret;
> 
>     st = avformat_new_stream(s, NULL);
>     if (!st)
>         return AVERROR(ENOMEM);
> 
>     ret = stream_params_copy(st, src);
>     if (ret < 0)
>         return ret;
> 
>     *dst = st;
> 
>     return 0;
> }
> 

I'd use AVStream *ff_stream_clone(AVFormatContext *dst_ctx, const
AVStream *src);

- Andreas


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