[mythtv-users] nuvexport ffmpeg video quality

[Gavin Hurlbut]

On Fri, May 27, 2011 at 3:19 AM, Paul Gardiner <lists at glidos.net> wrote:

> If you're looking into the inner workings of nuvexport then maybe you
> know more about mythtranscode than is available in it's documentation.
> I assume, for each command above, mythtranscode is running in
> parallel, sticking raw video and audio in the pipes. Would be great
> if you could answer a couple of questions.
>
> 1) mythtranscode typically replaces its source file with the
> transcoded version. Does it still do that when --fifodir
> is specified?
>

No, it doesn't.  It provides the raw video frames on one fifo, PCM audio on
another fifo, that is all.  It is read-only for the original recording.


2) Is it always raw video and audio that is output to the fifos, or
> does that depend on the profile specified? If it is always
> raw then does the profile have any affect on what is produced?
>

Always raw video, always full frame size, full frame rate, and YUV12
encoded.  For the audio, it's always PCM encoded audio (at whatever sampling
rate it is in the recording), and until recently (this may have changed with
some of JYA's tweaks), you get as many channels of PCM as there are audio
channels in the source.  I think this may have been changed somewhat.

I think JYA was also working on the possibility of passing the original
audio stream as is out the fifo, but I'm not sure if that's there or not.


> 3) Do you know the specific transcode calls that coresponded
> to the encoder commands above?
>

No.  We got rid of transcode as it was getting harder to support, and didn't
seem to have many users.  Or maybe I'm misunderstanding the question
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