Hi!

> From: Matto Marjanovic <[EMAIL PROTECTED]>
> 
> The delay was because I was planning to put up a good clear demonstration of
>  the benefits of using smil2yuv and y4mscaler in "4:1:1" mode to handle NTSC
>  DV video...
> 
> Anyhow, it certainly doesn't make anything *worse*.  If anyone (Steve?) wants
>  to try some independent tests, comparing MPEG-2 bitrates between "-i0" and
>  "-i2" in smil2yuv at the head of the chain, I'd be happy to see what happens.

        Someone mention my name? :)

        y4mscaler-0.4.1 and the latest smilutils were installed earlier this
        evening.  had a ~3 minute movie trailer's DV data (capture via a 
        Canopus ADVC100 of course ;)) handy to use a a test case.

        The only thing changed in the script was adding "-i 2" to the
        smil2yuv command, all other options to the filters and encoders
        were left unchanged.  

        I was not doing any scaling (the frames were the right size from
        earlier stages in the pipeline) but only the 4:1:1 to mpeg_4:2:0
        conversion with:

                 y4mscaler -O size=704x480 -O sar=src -O chromass=420_MPEG2

        First the summary from the old (without "-i 2" used with smil2yuv):

   INFO: [mplex] No. Pictures    :     5672
   INFO: [mplex] No. Groups      :      390
   INFO: [mplex] No. I Frames    :      390 avg. size 29313 bytes
   INFO: [mplex] No. P Frames    :     1520 avg. size 24700 bytes
   INFO: [mplex] No. B Frames    :     3763 avg. size 19660 bytes
   INFO: [mplex] Average bit-rate :  5028400 bits/sec
   INFO: [mplex] Peak bit-rate    :  7359600  bits/sec

        And now with "smil2yuv -i 2" and having y4mscaler do the conversion:

   INFO: [mplex] No. Pictures    :     5672
   INFO: [mplex] No. Groups      :      392
   INFO: [mplex] No. I Frames    :      392 avg. size 29102 bytes
   INFO: [mplex] No. P Frames    :     1521 avg. size 22934 bytes
   INFO: [mplex] No. B Frames    :     3760 avg. size 18612 bytes
   INFO: [mplex] Average bit-rate :  4755200 bits/sec
   INFO: [mplex] Peak bit-rate    :  7299200  bits/sec

        Wow.  Going from 5028400 to 4755200 is a significant difference - that's
        about 5% if my arithmetic skills haven't completely eroded.   The
        picture quality is good (I've only watched it on a monitor so far
        rather than a real TV).

        Guess I'll have to redo the entire 99 minute movie now ;)

        Cheers,
        Steven Schultz


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