[FFmpeg-devel] [PATCH] avformat/wavdec: allow to change max size of single demuxed packet

Andreas Rheinhardt andreas.rheinhardt at gmail.com
Fri Aug 28 11:41:20 EEST 2020


Paul B Mahol:
> On 8/28/20, Andreas Rheinhardt <andreas.rheinhardt at gmail.com> wrote:
>> Paul B Mahol:
>>> Can make demuxing much faster, expecially for files with
>>> huge number of channels.
>>>
>>> Signed-off-by: Paul B Mahol <onemda at gmail.com>
>>> ---
>>>  libavformat/wavdec.c | 21 ++++++++++++++++++---
>>>  1 file changed, 18 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/libavformat/wavdec.c b/libavformat/wavdec.c
>>> index e1b2115434..5b3c481421 100644
>>> --- a/libavformat/wavdec.c
>>> +++ b/libavformat/wavdec.c
>>> @@ -56,6 +56,7 @@ typedef struct WAVDemuxContext {
>>>      int smv_eof;
>>>      int audio_eof;
>>>      int ignore_length;
>>> +    int max_size;
>>>      int spdif;
>>>      int smv_cur_pt;
>>>      int smv_given_first;
>>> @@ -628,8 +629,6 @@ static int64_t find_guid(AVIOContext *pb, const
>>> uint8_t guid1[16])
>>>      return AVERROR_EOF;
>>>  }
>>>
>>> -#define MAX_SIZE 4096
>>> -
>>>  static int wav_read_packet(AVFormatContext *s, AVPacket *pkt)
>>>  {
>>>      int ret, size;
>>> @@ -706,7 +705,7 @@ smv_out:
>>>          wav->data_end = avio_tell(s->pb) + left;
>>>      }
>>>
>>> -    size = MAX_SIZE;
>>> +    size = wav->max_size;
>>>      if (st->codecpar->block_align > 1) {
>>>          if (size < st->codecpar->block_align)
>>>              size = st->codecpar->block_align;
>>> @@ -759,6 +758,7 @@ static int wav_read_seek(AVFormatContext *s,
>>>  #define DEC AV_OPT_FLAG_DECODING_PARAM
>>>  static const AVOption demux_options[] = {
>>>      { "ignore_length", "Ignore length", OFFSET(ignore_length),
>>> AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, DEC },
>>> +    { "max_size",      "max size of single packet", OFFSET(max_size),
>>> AV_OPT_TYPE_INT, { .i64 = 4096 }, 1024, 1 << 22, DEC },
>>>      { NULL },
>>>  };
>>>
>>> @@ -906,6 +906,20 @@ static int w64_read_header(AVFormatContext *s)
>>>      return 0;
>>>  }
>>>
>>> +#define OFFSET(x) offsetof(WAVDemuxContext, x)
>>> +#define DEC AV_OPT_FLAG_DECODING_PARAM
>>> +static const AVOption w64_demux_options[] = {
>>> +    { "max_size", "max size of single packet", OFFSET(max_size),
>>> AV_OPT_TYPE_INT, { .i64 = 4096 }, 1024, 1 << 22, DEC },
>>> +    { NULL },
>>
>> The ',' is unnecessary: Nothing will ever be added after the sentinel.
>>
>>> +};
>>
>> You can use &demux_options[1] instead of w64_demux_options (but add a
>> comment for this).
> 
> How the comment should look like?
> 

I thought of a comment for demux_options like "Hint: The options are
partially shared with the Wave64 demuxer."

>>
>>> +
>>> +static const AVClass w64_demuxer_class = {
>>> +    .class_name = "W64 demuxer",
>>> +    .item_name  = av_default_item_name,
>>> +    .option     = w64_demux_options,
>>> +    .version    = LIBAVUTIL_VERSION_INT,
>>> +};
>>> +
>>>  AVInputFormat ff_w64_demuxer = {
>>>      .name           = "w64",
>>>      .long_name      = NULL_IF_CONFIG_SMALL("Sony Wave64"),
>>> @@ -916,5 +930,6 @@ AVInputFormat ff_w64_demuxer = {
>>>      .read_seek      = wav_read_seek,
>>>      .flags          = AVFMT_GENERIC_INDEX,
>>>      .codec_tag      = (const AVCodecTag * const []) { ff_codec_wav_tags,
>>> 0 },
>>> +    .priv_class     = &w64_demuxer_class,
>>>  };
>>>  #endif /* CONFIG_W64_DEMUXER */
>>>
>>
>> _______________________________________________
>> 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".
> _______________________________________________
> 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