[mythtv-users] Re: nuv export speed

[Jonathan Markevich]

Chris Petersen wrote:

>> I tried to walk through the code to see what it was doing, but I got 
>> a little lost - it's very modularized but it's starting a dozen 
>> different processes with a billion different command-line options.  
>> (This is why we really need nuvexport!!!)  It's using mythtranscode, 
>> which I presume calls transcode... and I'm not sure if it's using 
>> ffmpeg or mpeg2enc.  ffmpeg on the web claims to be able to do 
>> real-time encoding.
>
> nuvexport calls mythtranscode if you have true nuv files, to set up 
> the raw a/v feed fifos.  From there, it either calls transcode 
> (dvd/vcd/xvid/others) or ffmpeg (wmv/mp3)  (both of which can interact 
> directly with mpeg-based files).  Transcode is also a wrapper of 
> sorts, and makes its own calls to various encoders.

Iiiiiinnteresting...  I tried selecting WMV instead of VCD, and I was 
getting about **70** fps instead of 7, no matter what bitrate I 
selected!  (still no denoising or anything else) The only problem is.. 
it's WMV.  Useless for further video processing.  Is there some way to 
shoehorn ffmpeg in there instead of mpeg2enc for MPEG1 encoding (even if 
it's not "official" VCD?)

> I have no idea why some people encode faster than others.  I do know 
> that transcode processes mpeg->mpeg faster than nuv/raw->mpeg (so 
> mpeg->vcd or mpeg->svcd).  But on that note, I just started a vcd 
> export with no denoise (major slowdown) and am getting around 15fps on 
> my 2.4G p4 (that's with mpeg4 nuv files)


This could well be it.  I have mpeg4 files too, because I have a bttv 
card.  The only time it sees mpeg is when I export.

Man I think we're on to something.  BTW.  I grok the nuvexport module 
layout a bit better now.  It's nice and clean.  I was able to get it to 
pass different parameters in to transcode, though it didn't really 
change anything.