On Thu, 17 Feb 2005 06:29:52 -0500 (EST), Cory Papenfuss <[EMAIL PROTECTED]> wrote: > > 4) avidemux2 will split the MPEG2-PS contents of the .nuv files into > > component .m2v video and .mp2 audio, using the cutlist to clip out > > commercials (using Xvfb to hide the gui from you) > > This step here needs to be avoided... this is where the sync > issues are caused. > > > nuvexport > > > > 1) Use nuvexport's mpeg2 -> mpeg2 cut option to export and > > commercial-cut your shows from Mythtv into standalone .mpg files. > > (which is using the same avidemux index, split/cut, lvemux re-combine > > process as above, all with Xvfb to hide the gui) > > > > Again, if avidemux2 is used directly on the mpeg2 .nuv files, > glitches in the stream that cause a change in A/V offset will break sync. > Avidemux does not handle changing sync... only a static offset from > beginning to end (which 95% of ivtv recordings have so it works most of > the time) > > > Video Quality > > > > Once you get one of these processes working, you still may not be > > satisfied with the results. For example, I don't have my PVR-350 TV-out > > working yet, so I'm using an nVidia GeForce 2mx S-video output to my TV > > for now. I'm reasonably happy with the video quality given that my > > analog cable input is pretty bad to start with. > > > If recorded at a DVD-friendly resolution with enough bitrate, the > quality should be OK. I've found in general you need a fair bit more > bitrate than a commercial DVD since the noise in the signal does not > compress well. > > My viewpoint is that there are a few underlying issues that need > to be solved: > > 1. Correct lossless MPEG2->MPEG2 cutting. This one has not been > successfully done yet with any tools that I have found (mythtv or > otherwise). Tools like GOPchop are close, but they're a little rough > around the cutpoints. The potentially-changing A/V offset makes demuxing > and remuxing impossible (at least without adding padding frames or > something to fix sync variations). The elementary streams have *no* sync > information as I understand it. This would provide space savings on > archived mythtv recordings by removing the commercials without taking the > time or the quality hit of transcoding. > > 1a. MPEG2->MPEG2 transcoding. Not completely without merit. The > hardware scaling in the PVR-[23]50 cards makes for lousy recordings below > 480x480, but burning up 704x480 resolution for a broadcast tv signal is > wasteful of the space. My personal archival process involves recording at > something fairly high (640x480) with a high bitrate, and then two-pass > transcoding (with some denoising) to 352x480. That final image is *much* > better than recording at 352x480 directly on the PVR-250, and is quite > adequate for archiving broadcast-quality to DVD. I get about 4 hours of > video on a DVD at VHS-SP quality. If I were to cut it down to <4 hours, > it'd be even better than VHS-SP. > > 2. DVD authoring. *ONLY* after #1 (or #1a) are solved should anyone even > think of messing with a fancy DVD authoring GUI. It's rather complicated > to do well, and especially complicated to have menus with buttons, > graphics, etc. That's a completely separate animal from having correct, > cut MPEG2 files to begin with.
Cory, Could you post the full details of what you do to take a recording and convert it to a video DVD? Thanks, Lane -- Meetup with other Myth users! http://mythtv.info/moin.cgi/MUG
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