[FFmpeg-devel] [PATCH] avformat/concatdec: don't call open_file when seek position within a file

[raymond zheng]

ping...

2016-09-20 15:04 GMT+08:00 raymond zheng <raymondzheng1412 at gmail.com>:

> Submit reasons:
>
> I have enabled concat and async protocol,but ffmpeg will flush async
> buffer when doing seek. I don't want flush async buffer when doing seek
> within the same segment file.
> I found, the concatdev will call open_file everytime I try to do seek,
> which will cause call async_open,and then flush async buffer.
>
>
> Solution:
>
> I will judge if seek range in the same segment file, if so, I‘ll only call
> try_seek.
>
>
> 2016-09-20 12:31 GMT+08:00 raymond <raymondzheng1412 at gmail.com>:
>
>> ---
>>  libavformat/concatdec.c | 27 ++++++++++++++++++++-------
>>  1 file changed, 20 insertions(+), 7 deletions(-)
>>
>> diff --git a/libavformat/concatdec.c b/libavformat/concatdec.c
>> index b3a430e..1cd9ec1 100644
>> --- a/libavformat/concatdec.c
>> +++ b/libavformat/concatdec.c
>> @@ -64,6 +64,8 @@ typedef struct {
>>      ConcatMatchMode stream_match_mode;
>>      unsigned auto_convert;
>>      int segment_time_metadata;
>> +    int cur_fileno;
>> +    AVFormatContext *cur_avf_saved;
>>  } ConcatContext;
>>
>>  static int concat_probe(AVProbeData *probe)
>> @@ -333,6 +335,8 @@ static int open_file(AVFormatContext *avf, unsigned
>> fileno)
>>          avformat_close_input(&cat->avf);
>>          return ret;
>>      }
>> +
>> +    cat->cur_fileno = fileno;
>>      cat->cur_file = file;
>>      if (file->start_time == AV_NOPTS_VALUE)
>>          file->start_time = !fileno ? 0 :
>> @@ -711,13 +715,18 @@ static int real_seek(AVFormatContext *avf, int
>> stream,
>>              left  = mid;
>>      }
>>
>> -    if ((ret = open_file(avf, left)) < 0)
>> -        return ret;
>> +    if (cat->cur_fileno != left) {
>> +        if ((ret = open_file(avf, left)) < 0)
>> +            return ret;
>> +    } else {
>> +        cat->avf = cat->cur_avf_saved;
>> +    }
>>
>>      ret = try_seek(avf, stream, min_ts, ts, max_ts, flags);
>>      if (ret < 0 &&
>>          left < cat->nb_files - 1 &&
>>          cat->files[left + 1].start_time < max_ts) {
>> +        cat->avf = NULL;
>>          if ((ret = open_file(avf, left + 1)) < 0)
>>              return ret;
>>          ret = try_seek(avf, stream, min_ts, ts, max_ts, flags);
>> @@ -730,7 +739,7 @@ static int concat_seek(AVFormatContext *avf, int
>> stream,
>>  {
>>      ConcatContext *cat = avf->priv_data;
>>      ConcatFile *cur_file_saved = cat->cur_file;
>> -    AVFormatContext *cur_avf_saved = cat->avf;
>> +    cat->cur_avf_saved = cat->avf;
>>      int ret;
>>
>>      if (!cat->seekable)
>> @@ -739,12 +748,16 @@ static int concat_seek(AVFormatContext *avf, int
>> stream,
>>          return AVERROR(ENOSYS);
>>      cat->avf = NULL;
>>      if ((ret = real_seek(avf, stream, min_ts, ts, max_ts, flags)) < 0) {
>> -        if (cat->avf)
>> -            avformat_close_input(&cat->avf);
>> -        cat->avf      = cur_avf_saved;
>> +        if (cat->cur_file != cur_file_saved) {
>> +            if (cat->avf)
>> +                avformat_close_input(&cat->avf);
>> +        }
>> +        cat->avf      = cat->cur_avf_saved;
>>          cat->cur_file = cur_file_saved;
>>      } else {
>> -        avformat_close_input(&cur_avf_saved);
>> +        if (cat->cur_file != cur_file_saved) {
>> +            avformat_close_input(&cat->cur_avf_saved);
>> +        }
>>          cat->eof = 0;
>>      }
>>      return ret;
>> --
>> 2.7.4
>>
>>
>