[FFmpeg-devel] [PATCH] Set AVStream duration in several demuxers

[Michael Niedermayer]

On Mon, Jan 18, 2010 at 10:43:06PM -0500, David Conrad wrote:
> Hi,
> 
> Several demuxers set duration and start_time in AVFormatContext, despite the comment to never set them directly. This sets them in AVStream instead, fixing "Estimating duration from bitrate, this may be inaccurate" messages.
> 
> iavs/ivas AVIs still set AVFormatContext duration, I didn't find a sample to test.
> 

> commit d1ec4470be04fba3ff10fbecd455a14ab322d14e
> Author: David Conrad <lessen42 at gmail.com>
> Date:   Mon Jan 18 22:33:25 2010 -0500
> 
>     Set start_time and duration in AVStream not AVFormatContext.
>     The latter is deduced from the former.
> 
[..]
> diff --git a/libavformat/flvdec.c b/libavformat/flvdec.c
> index 9c43149..0382a7b 100644
> --- a/libavformat/flvdec.c
> +++ b/libavformat/flvdec.c
> @@ -124,6 +124,7 @@ static int amf_parse_object(AVFormatContext *s, AVStream *astream, AVStream *vst
>      AMFDataType amf_type;
>      char str_val[256];
>      double num_val;
> +    int i;
>  
>      num_val = 0;
>      ioc = s->pb;
> @@ -192,7 +193,9 @@ static int amf_parse_object(AVFormatContext *s, AVStream *astream, AVStream *vst
>          } else if(amf_type == AMF_DATA_TYPE_NUMBER) {
>              snprintf(str_val, sizeof(str_val), "%.f", num_val);
>              av_metadata_set(&s->metadata, key, str_val);
> -            if(!strcmp(key, "duration")) s->duration = num_val * AV_TIME_BASE;
> +            if(!strcmp(key, "duration"))
> +                for (i = 0; i < s->nb_streams; i++)
> +                    s->streams[i]->duration = num_val * 1000;
>              else if(!strcmp(key, "videodatarate") && vcodec && 0 <= (int)(num_val * 1024.0))
>                  vcodec->bit_rate = num_val * 1024.0;
>          } else if (amf_type == AMF_DATA_TYPE_STRING)

if duration is defined in the spec as the duration of all streams (compared
to the duration of the longest stream) then ok


[...]
> @@ -362,7 +364,7 @@ static int flv_read_packet(AVFormatContext *s, AVPacket *pkt)
>   }
>  
>      // if not streamed and no duration from metadata then seek to end to find the duration from the timestamps
> -    if(!url_is_streamed(s->pb) && s->duration==AV_NOPTS_VALUE){
> +    if(!url_is_streamed(s->pb) && s->streams[0]->duration==AV_NOPTS_VALUE){
>          int size;
>          const int64_t pos= url_ftell(s->pb);
>          const int64_t fsize= url_fsize(s->pb);
> @@ -372,7 +374,8 @@ static int flv_read_packet(AVFormatContext *s, AVPacket *pkt)
>          if(size == get_be24(s->pb) + 11){
>              uint32_t ts = get_be24(s->pb);
>              ts |= get_byte(s->pb) << 24;
> -            s->duration = ts * (int64_t)AV_TIME_BASE / 1000;
> +            for (i = 0; i < s->nb_streams; i++)
> +                s->streams[i]->duration = ts;
>          }
>          url_fseek(s->pb, pos, SEEK_SET);
>      }

finding one timestemp from one stream is only good for one duration

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Rewriting code that is poorly written but fully understood is good.
Rewriting code that one doesnt understand is a sign that one is less smart
then the original author, trying to rewrite it will not make it better.
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