[mythtv] Re: nuvexport mpeg2cut doesn't work on dvb-t mpeg

Gavin Hurlbut gjhurlbu+mythtv-dev at beirdo.ca
Thu Nov 18 17:58:08 UTC 2004

Thomas Husemann <thomas at thusemann.dyndns.org> wrote:
> I tried to cut my recording with nuexport. The recording was produced by 
> dvb-t card (AverMedia DVB-T 771). First problem was the Xvfb server. My 
> solution:

Oh fun.  :)

> -    ${XVFB} :13 -screen 0 640x480x8 2> /dev/null > /dev/null &
> +    ${XVFB} :13 -ac -screen 0 640x480x8 2> /dev/null > /dev/null &

Hmmm.  Disabling access controls...  I guess that's not a bad idea.  I'll work
that in.  I also had someone else who needed to run in 24 colour mode for soem
reason, so I'll likely put that in too.

> mpeg2cut /mnt/store/1006_20041117101800_20041117104500.nuv "./King of 
> Queens -In Flagranti".mpg  2521-18637 30102-45445 45537-

OK, there's the first problem.  Seems that myth isn't putting in GOP frame 
indexes into the database for your video.  Without that, we have no idea what
the last frame number will be, and hence we can't cut...

Soooo.  Could you get me a dump of *one* show's worth of recordedmarkups 
database entries?  You'd need to be handy with SQL, and preferrably use a short
recording.  Please email it to me directly.

> mpeg2cut v1.6
> Using mode Xvfb
> Filename "/mnt/store/1006_20041117101800_20041117104500.nuv"
> OutFile "./King of Queens -In Flagranti.mpg"
> Last GOP index 2521-18637

Baaaaad. :)

> *more debug* (with set -x and stderror)

Ahhh, learn something new every day.

>   720 x 576 at 25000 fps
>  >>>Other PTS = 3208911210

>   could not get sync!

> **error reading packet**

>   io error , aborting sync

>   end of stream...

Also bad...   Seems avidemux barfs on your MPEG files.  It seems that maybe
Myth isn't actually generating a proper MPEG2-PS file from the MPEG2-TS stream
perhaps?  Hard to tell so far.

If it can't index, it's game over.

> *tcprobe from mpegstream*

> [tcprobe] MPEG program stream (PS)
> [tcprobe] summary for /mnt/store/1006_20041117101800_20041117104500.nuv, 
> (*) = not default, 0 = not detected
> import frame size: -g 720x576 [720x576]
>       aspect ratio: 4:3 (*)
>         frame rate: -f 25.000 [25.000] frc=3
>                     PTS=35655.2287, frame_time=40 ms, bitrate=15000 kbps
>        audio track: -a 0 [0] -e 48000,16,2 [48000,16,2] -n 0x50 [0x2000] (*)
>                     PTS=35654.5690, bitrate=192 kbps
>                     -D 16 --av_fine_ms 19 (frames & ms) [0] [0]
> detected (3) presentation unit(s) (SCR reset)

Hmmm.  3 presentation units?  Interesting, never seen that with my ivtv
generated files.

I do have some test recordings to test with tonight, so I'll see if I can dig
anything up.

In the mean-time, it looks like mpeg2cut will not work for your recordings.
Hold on a few days, I'll try to fix that. :)


> Any suggestions ?

> Regards

> Thomas

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