On Tue, 18 Oct 2005, [ISO-8859-1] Bernhard Fr?hmesser wrote:
> I have tested this, mpeg2dec ofile.m2v -o pgmpipe | pgmtoy4m -i t -a 1:1
> -r 30000:1001 -x 420mpeg2 > test.mov
I hope you weren't expecing to get a Quicktime file from 'pgmtoy4m' ;)
As the name implies pgmtoy4m is a PGM(mpeg2dec) to YUV4MPEG2 (also
known as Y4M) program not a Quicktime (.mov) wrappering program.
Coming from a DVD I really do not think square pixels (-a 1:1) is the
proper setting. If it's a non-widescreen "NTSC" then 10:11 is the
value, widescreen NTSC is 40:33. http://www.mir.com/DMG/aspect.html
is a good place to bookmark ;)
Even for testing I think it's a good idea to use the correct aspect
values.
> But when i do a lavplay later on test.mov i get:
> Unable to identify file (not a supported format - avi, quicktime).
That is to be expected since "Y4M" data is neither avi or quicktime.
Simply putting a .mov in a filename doesn't cause a transformation
from Y4M data to a Quicktime wrapper.
> So i am not sure if pgmtoy4m can "store" the output in a file which i
> can use with glav/lavplay etc... as the stuff in the manpage doesn't
I guess I read too quickly thru the goal you're trying to achieve.
I (mistakenly) thought you were simply trying to recode a DVD to
a different format.
> Also the audio won't be available here, so i guess ffmpeg or mencoder
> will be better here to have the audio too.
Extract the audio to a separate file. Any decent editor will have
the ability to import the video and audio from different files.
Editing MPEG-2 video can be done one of three ways:
1. Edit with GOP sized resolution (typical DVDs are about 15
per GOP or about .5 seconds) with something like ProjectX
http://www.lucike.info/ - then export new files (audio and video)
which can be mplex'd together.
2. A lossless decode to uncompressed Y'CbCr, do the editing, export
the data to a new uncompressed file and encode. There will be
some loss of quality due to the re-encoding but it's not too bad.
3. Decode the original MPEG-2/VOB file, do a lossy encode to something
glav understands (MJPEG or DV), edit, decode the MJPEG or DV,
encode to MPEG-2. If you encode to DV25 then Kino could be used
to do the editing. I've seen the results of going thru an
intermediate lossy compression step and it's not pretty ;(
For #2 perhaps Cinelerra can handle uncompressed video.
The couple times I've done this type of thing I supersampled the
chroma from 4:2:0 to 4:2:2 (using y4mscaler) and created a '2vuy'
(uncompressed 4:2:2) Quicktime file from the Y4M data (using a hack
written for the purpose). Editing and rendering was done using
Final Cut Pro.
> BTW i might recompile the mjpegtools here as i get "Segmentation fault"
> very often. Either i recompile version 1.8.0 or get back to 1.6.2.
Can't fix what hasn't been reported. We're not mind-readers ;)
A better bug report than "I get segmentation fault very often" would
be a good start :-) Knowing what program(s) were crashing would also
be useful information.
I haven't had an segment faults in the encoder or multiplexor (mpeg2enc
or mplex).
There is a memory leak in the Quicktime audio handling - if you're
seeing crashes due to memory allocation there's a small patch
in the recent mailinglist archives. It's been fixed in CVS of course ;)
Cheers,
Steven Schultz
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