Hi all, I've been working with Linux & video for some time now, mostly with Kino, Cinelerra and occasionally CLI tools (mplex, mencoder). The question I have deals with one of the elusive Holy Grails of video processing: how to render a given DV file into the highest possible quality DVD.
So far, I found it often is a matter of trial, (long) wait and error: render a DV file from within Cinelerra, first to an AC3 audio file, then with YUV4MPEG and a pipe (see below) to an m2v video file, then use mplex to merge both files, only to find that either the maximum bit rate and/or quantization value for DVD has been exceeded. After which I adjust the appropriate value, and start rendering again. Sometimes it takes three attempts to reach the optimal values, and with render times of sometimes up to a few hours each (on an AMD64 dual-core machine, at that), this is a rather time-consuming procedure. Example of the render pipe command: yuvcorrect -v 0 -T INTERLACED_BOTTOM_FIRST | mpeg2enc -M 2 -v 0 -r 32 -4 1 -2 1 -D 10 -g 15 -G 15 -q 5 -b 9600 -f 8 -o % It would be nice if there was a tool to calculate which values for bit rate and quantization would still result in a valid DVD MPEG file, based on a given DV file, without actually having to go through the lengthy rendering process itself. Does such a 'video complexity analyzer' exist? I couldn't find anything, but I'm still rather unfamiliar with the actual intricacies of MPEG and the likes. Alternatively, I've looked at ways to make rendering script-driven, so that a CLI script could automatically perform the rendering attempts, and adjust the -b and -q parameters, based on mplex output. This way, one could simply have the whole thing running overnight, with more or less optimized results some time the next day. Unfortunately, Cinelerra doesn't allow for CLI driven rendering other than the rather inflexible batch render functions, and I though I found that rendering an edited project first to DV, then rendering the DV file to MPEG, gives a noticeable quality degradation. So, are there any thoughts on this? Thanks in advance, regards, Richard Rasker ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Mjpeg-users mailing list Mjpeg-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mjpeg-users
