> On Tue, May 30, 2006 at 03:36:13PM +0200, Herman Robak wrote: > > I offer 200 Euro to the one who adds MPEG Program Stream as one > > of Cinelerra's output formats, with a DVD compability setting. > > > > Cinelerra already supports rendering raw MPEG video and audio streams, > > but not simultaneously, and no multiplexing. This means Cinelerra > > can not render DVD-ready MPEG2 files directly. > > That's a great bounty, Herman! > > In case anyone is thinking about this, one way to accomplish this > would be changing the DV output so it can be written to a pipe. > Currently, it uses fseek's that can only be done on files. Once it > can be piped out, one can use the ffmpeg toolchain to convert to from > piped DV to the finished DVD-ready output on the fly.
There are several reasons why this is not IMHO a desirable approach. As someone has already pointed out, doing this incurs the time penalty of a DV encode/decode cycle - although admittedly if the source happens to be in DV *and* there's no video processing active the cycle will be skipped. The biggest problem is that libdv's PAL encoder is buggy (I've never tried NTSC) and introduces considerable artifacts which are particularly noticeable during moderate horizontal movement. ffmpeg is better but still (as of 6 months ago anyway) had problems. Besides this, there will be a loss of quality due to the decode/encode cycle since DV is lossy. Most videos do have at least some transisitions/overlays etc, so this issue will crop up, even if it doesn't affect a majority of a video if the source is DV. For this reason using DV as the intermediate format is not ideal. However, perhaps the DV framework could be used as the basis for something since as has been pointed out, the DV export option is one of few (perhaps the only one?) which does video and audio simultaneously. Regards jonathan _______________________________________________ Cinelerra mailing list [email protected] https://init.linpro.no/mailman/skolelinux.no/listinfo/cinelerra
