[mythtv-users] Odd sync problem on ffmpeg convert of NUV files

[John Sturgeon]

Ackster wrote:

> So I am trying to convert some PBS programs from the HD-3000 recorded 
> NUVs to DVD MPEG2 format.  I installed nuvexport to make my life a 
> little easier, and it works on converting my recordings to MPEG4, 
> which I believe is using transcode and not ffmpeg.  The convert to DVD 
> however is a problem.  It looks like FFMPEG is not working correctly 
> because the resulting file is corrupted in that there is a color frame 
> sync problem (for lack of a better term).  It hard to describe it, so 
> check out this sample :
>
> http://webpages.charter.net/jk9898/
>
> Suggestions?
>
> MythTV 0.17
> ffmpeg is version 0.4.9pre1, build 4732
>
> -Ack

Not sure what settings you are using to convert, but there are a couple 
things that you need to be aware of when encoding for DVD's ]
1) there are bit-rate limitations (I can't remember off the top of  my 
head, but somewhere in the neighborhood of 10k MAX including audio) 
which can *never* be exceeded. 2) there are also resolution requirements.

Since the HD-3000 already captures MPEG2 streams, you really are mainly 
concerned with resizing, and resampling to a lower bit-rate.

O.K.

I downloaded the file, and tcprobe -i tells me:
[mythtv at localhost completed]$ tcprobe -i sample.mpg
[tcprobe] MPEG program stream (PS)
[tcprobe] summary for sample.mpg, (*) = not default, 0 = not detected
import frame size: -g 720x480 [720x576] (*)
    aspect ratio: 1:1
      frame rate: -f 23.976 [25.000] frc=1 (*)
                  PTS=0.5000, frame_time=41 ms, bitrate=104857 kbps
     audio track: -a 0 [0] -e 48000,16,2 [48000,16,2] -n 0x50 [0x2000] (*)
                  PTS=0.5000, bitrate=384 kbps
                  -D 0 --av_fine_ms 0 (frames & ms) [0] [0]

This tells me your bitrate is through the roof.  You probably want to 
pull your video bitrate down to the 8k range.

-- 
John Sturgeon <><
http://www.sturgeonfamily.com/mythtv.php