[mythtv-users] Conversion to DVD

Stuart Hodges mymythtv at twotails.org
Thu Nov 6 21:34:45 EST 2003


Hi,

	I compiled avidemux2, all seems to work fine until I try to multiplex. Then I 
get droped frames, thus:

mplex -f 8 audio.try1.mp2 video.try1.m2v -o mpg.try1.mpg
   INFO: [mplex] mplex version 2.2.1 ($Date: 2002/02/04 19:06:14 $)
   INFO: [mplex] File audio.try1.mp2 looks like an MPEG Audio stream.
   INFO: [mplex] File video.try1.m2v looks like an MPEG Video stream.
   INFO: [mplex] Found 1 video streams 1 MPEG audio streams and 0 AC3 streams
   INFO: [mplex] Selecting DVD output profile (INCOMEPLETE!!!!)
   INFO: [mplex] Scanning for header info: Video stream e0 (video.try1.m2v)
   INFO: [mplex] VIDEO STREAM: e0
   INFO: [mplex] Frame width     : 720
   INFO: [mplex] Frame height    : 480
   INFO: [mplex] Aspect ratio    : 4:3 display
   INFO: [mplex] Picture rate    : 29.970 frames/sec
   INFO: [mplex] Bit rate        : 16000000 bits/sec
   INFO: [mplex] Vbv buffer size : 229376 bytes
   INFO: [mplex] CSPF            : 0
   INFO: [mplex] Scanning for header info: Audio stream c0 (audio.try1.mp2)
   INFO: [mplex] AUDIO STREAM:
   INFO: [mplex] Audio version  : 1.0
   INFO: [mplex] Layer          :        3
   INFO: [mplex] CRC checksums  :       no
   INFO: [mplex] Bit rate       :    49152 bytes/sec (384 kbit/sec)
   INFO: [mplex] Frequency      :     48000 Hz
   INFO: [mplex] Mode           :        0 stereo
   INFO: [mplex] Mode extension :        0
   INFO: [mplex] Copyright bit  :        0 no copyright
   INFO: [mplex] Original/Copy  :        0 copy
   INFO: [mplex] Emphasis       :        0 none
   INFO: [mplex] SYSTEMS/PROGRAM stream:
   INFO: [mplex] rough-guess multiplexed stream data rate    : 16648800
   INFO: [mplex] target data-rate specified               : 10080000
++ WARN: [mplex] Target data rate lower than computed requirement!
++ WARN: [mplex] N.b. a 20% or so discrepancy in variable bit-rate
++ WARN: [mplex] streams is common and harmless provided no time-outs will 
occur
   INFO: [mplex] Sectors = 89 Video delay = 13019 Audio delay = 13019
   INFO: [mplex] New sequence commences...
   INFO: [mplex] Video e0: buf= 237568 frame=000000 sector=00000000
   INFO: [mplex] Audio c0: buf=   4096 frame=000000 sector=00000000
++ WARN: [mplex] Stream e0: data will arrive too late sent(SCR)=37156 
required(DTS)=37043
++ WARN: [mplex] Video e0: buf= 181219 frame=000008 sector=00000246
++ WARN: [mplex] Audio c0: buf=   3783 frame=000012 sector=00000007

etc, until:

**ERROR: [mplex] Too many frame drops -exiting

	The few seconds of multiplexed video look fine, I think I have everything set 
fine in mythtv, any ideas what I am doing wrong ?

	Thanks,

		Stuart

On Tuesday 04 November 2003 04:44, James L. Paul wrote:
> 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
>
> _______________________________________________
> mythtv-users mailing list
> mythtv-users at mythtv.org
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users



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