[mythtv-users] Conversion to DVD

[James L. Paul]

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On Monday 03 November 2003 15:50, matt hatfield wrote:
> > Hi,
> >
> >         I am using MYTHTV successfully with a PVR-350. Occasionally I
> > want to
> > save
> > something to DVD.
> >
> >         The posting " Re:Burning DVD's from inside the Myth" says :
> > (It's just a matter of demuxing, remuxing with
> > NAV markers, then dvdauthor, mkisofs, cdrecord.)
> >
> >         I get the dvdauthor, mkisofs, cdrecord bit, but the best I can do
> > is :
> >
> > 1) Mencoder to convert to mjpeg and WAV.
> > mencoder -o OUTPUT_FILE -ofps 30 -ovc lavc -lavcopts
> > vcodec=mjpeg:vhq:vqmin=2:vqmax=10 -oac pcm INPUT_FILE
> >
> > 2) reencode video
> > cat OUTPUT_VIDEO | yuvscaler -O SIZE_720x480 | mpeg2enc -F4 -f 8 -q 5 -4
> > 1 -2
> > 1 -P -N -o VIDEO.m2v
> >
> > 3) reencode audio
> > lav2wav  OUTPUT_AUDIO | mp2enc -r 48000 -o AUDIO.mp2
> >
> > 4) Remultiplex
> > mplex -f 8 SOUND.mp2 VIDEO.m2v -o CONVERTED.mpg
> >
> > Then dvddirgen etc.
> >
> > I also have to cut the input video up on input to stop audio drift.
> >
> > This takes a long time (14 hours processing time on a AMD 2100+) and the
> > output quality is not very good, loads of artifacts that were not in the
> > original video.
> >
> > I tried using ffmpeg to create the mjpeg to get around using mencoder,
> > but yuvscalar did not like it.
> >
> > Any ideas ?
> >
> >         Thanks,
> >
> >                 Stuart
> > _______________________________________________
> > mythtv-users mailing list
> > mythtv-users at mythtv.org
> > http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>
> Might not be the exact answer you are looking for, but I have done much
> experimenting with this myself. I have come to the conclusion that this is
> about the only place that windows has linux beat. I beleive that the files
> made by the PVR-350 are the same format as PVR-250. If this is correct you
> can use TMPGENC DVD Author to drop the file right onto a DVD no
> re-encoding or anything. I couldn't find a linux equivilant no matter how
> hard I tried. The total time from start to finish is about 30 - 35 minutes
> including burn time. I encode my recordings at 4400 with a 8800 peak 384
> audio. The DVD's look great just like I was watching the show. Again I am
> not sure if this is what you are looking for but it does work.

Windows definitely is in the lead for MPEG editing tools and DVD authoring 
tools. But I finally found it possible to at least go from MythTV PVR-250 to 
DVD and edit out commercials, even if not simply or automated.

Definitely eliminate re-encoding. First of all, make sure your capture specs 
match a valid DVD compliant format. I use 352x480 and 48000/224 audio, but 
you can use 720x480 just as well. I don't recommend any others.

The only thing that usually outright prevents dvdauthor from accepting the 
PVR-250 file as-is is the lack of the NAV placeholders. tcmplex and mplex can 
multiplex these in, I use mplex. Of course, before you can mplex you need to 
demultiplex the program stream file (.mpg) into elementary streams (.m2v & 
.mp2).

My struggle has been finding tools that can do this properly so that both 
elementary files are useable to further tools. The mpgtx tool can do it as 
long as you do the whole file without any cuts. Older versions of avidemux 
won't recognize the PVR-250's files correctly. Older versions of avidemux2 
would almost work, but broke the audio. GOPchop gave useable audio but broke 
video.

Behold, the mid-October latest version of avidemux2 has been updated to 
properly recognize the PVR-250's audio and is useable. Don't let the name 
fool you, you won't need to use any of the AVI features of avidemux2. ;) 
Instead of creating an AVI file, you can instead "save raw video" to get the 
.m2v file. If you leave audio processing disabled, the "Save Audio" will save 
the raw audio in .mp2 format. Any cut markers you have selected will be in 
effect, so you can save m2v/mp2 sets for each segment between commercials.

Feed these sets to mplex using "-f 8" to get the NAV placeholders, and the 
resulting segments will be palatable to dvdauthor.

I just finished a DVD today that contains seven episodes of Family Guy that 
were sitting on my MythTV box, with a main menu to select which episode to 
watch. I used this method:

Use avidemux2 to cut the program into commercial-free segments of m2v/mp2 
files.
mplex each set together using -f 8 to get one mpg file per segment.
Create a menu.mpg appropriate for this DVD. (a whole other topic)
mkdir mydvd
dvdauthor -o mydvd file1.mpg file2.mpg ...
dvdauthor -T -o mydvd -m <button defs> <menu.mpg> -P
Then it's just the old mkisofs -dvd-video and cdrecord steps.

avidemux can be called from command line, so it's pretty easy to automate the 
creation of an uncut simple single-title menuless DVD. I haven't written any 
generalize scripts though, just my own shell script for my specific files 
that I hand-edit each time. I've got a lot of little things I'm still trying 
to perfect. ;)

> Matt
> _______________________________________________
> mythtv-users mailing list
> mythtv-users at mythtv.org
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
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