On Tue, 24 May 2005, Jean Connelly wrote:
> Well, I tried searching for strings including things like: hdtv, dvd,
> scaling, y4mscaler, yuvscaler, mpeg2enc, 1080i ... in various
Hmm, strange - I would have expected a few signficant hits when
searching the mjpeg-dev and -users lists.
> I got a few hits for encoding hdtv, but I didn't find anything for
> getting good dvd mpeg2 from it.
Try searching the mjpeg-users and -devel lists and add my name to
the search criteria :-)
> > Hmmm, I prefer to use ProjectX and mpeg2dec. ProjectX not only
>
> Project X seems to choke on all of my TS files. Avidemux2 will at
Which version of ProjectX are you using? The latest one (0.82.x)
doesn't run right for me at all even on files which were known to
be good. I fell back to ProjectX-0.81.9 and all is well.
> Anyway, I've been playing back those cuts from avidemux2 with mplayer
> -> y4mscaler -> mpeg2enc.
One thing to watch out for with mplayer...
> interlaced by eye, but which was marked "progressive" by yuvscaler
> after being passed by mplayer. I'll experiment with your suggestions
... is that it gets the YUV4MPEG2 header wrong. One of the things
it "guesses at" is the interlacing ('I' tag in the YUV4MPEG2 header).
The other thing can be the sample aspect ratio ('A' tag), and finally
the frame rate ('F') tag can appear as 'F29969999:1000000' instead
of 30000/1001.
Basically a correct YUV4MPEG2 header looks like this:
YUV4MPEG2 W720 H480 F30000:1001 It A10:11 C420mpeg2
while MPlayer will emit this:
YUV4MPEG2 W720 H480 F29969999:1000000 Ip A0:0
Basically everything's progressive and has an unknown sample aspect
ratio. You'll need to override a number of thing -starting with the
fact that it's not really progressive ('Ip').
NOTE: with HDTV the pixels are square (the script I posted takes this
into account) so the 'A' tag would be 1:1 (the example above was from
a .m2v file I had laying around and thus the SAR is 10:11).
There are tools in mjpegtools that can fix up the header (it's a bit
ugly but it works ;)). You can use 'y4mtoyuv' to strip off the bogus
header, and then use 'yuvtoy4m ...' to explicity specify all attributes
of the stream (in essence generate a new complete header).
Cheers,
Steven Schultz
-------------------------------------------------------
This SF.Net email is sponsored by Yahoo.
Introducing Yahoo! Search Developer Network - Create apps using Yahoo!
Search APIs Find out how you can build Yahoo! directly into your own
Applications - visit http://developer.yahoo.net/?fr=offad-ysdn-ostg-q22005
_______________________________________________
Mjpeg-users mailing list
Mjpeg-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/mjpeg-users
