[mythtv-users] Problem with MPEG-4 transcoded file (no bitrate or duration)

[John Pilkington]

On 17/05/2019 15:59, mythtv at kosowsky.org wrote:
> John Pilkington wrote at about 08:49:48 +0100 on Tuesday, May 14, 2019:
>   > On 14/05/2019 01:30, mythtv at kosowsky.org wrote:
>   >
>   > > Perhaps a partial clue is that under v24, the transcoded file had an
>   > > 'nuv' suffix while under v29.1 the suffix is 'ts'.
>   > > Could it be an issue with the container?
>   > >
>   > > Note that ffprobe shows both files to be of format NuppelVideo.
>   > >
>   >
>   > That is the problem.  NuppelVideo is now seen as an an outdated format
>   > and support for it is fading away, even if it hasn't been officially
>   > dropped.  It might be dependent on the options used in the build of
>   > ffmpeg or mythffmpeg that you are using.
>   >
>   > Google found this, but I guess you have already seen it:
>   >
>   > https://www.mythtv.org/wiki/MythTV-HOWTO_-_0.27
> 
> 
> I think I've made some progress.
> It seems perhaps that myttranscode now transcodes into HTTP streaming
> format which could explain lack of duration.
> 
> When I use ffmpeg to copy (and concatenate) the streams, I then get a
> valid duration:
>     ffmpeg -y -i <file.ts>  -c copy  <file2.ts>
> 
> However, when I do that, for some reason the keyframes/i-frames are
> lost... so when I 'edit' no frames show up.
> 
> Also, 'mythcommflag --rebuild', gives the following error:
>        No I-frames found, rewinding...
> 
> 
> So, is there any way to use ffmpeg to rebuild the stream in a way
> that:
> 1. Creates a single stream with a duration
> 2. Preserves the frames/i-frames/keyframes
> 
> 
> Also, it's possible that I am way off base here...
> 
> Jeff

Interesting, and news to me.  I thought the problem was with ffmpeg 
because you reported that ffmpeg -i and ffprobe were giving different 
readings.  My googling for NuppelVideo also brought up a long ticket 
about Peter's refactoring for ffmpeg a year or so ago.  I'm currently on 
a laptop and can't consult that search history.

John P