Hi, all,
I'm trying to squeeze 2+ hours of NTSC onto a 4.7GB DVD. Previously, I
got advice on using 2-pass ffmpeg processing to reduce the bitrate.
(See http://e.kevb.net/lurker/message/20090303.175900.5c71d6c8.en.html)
But, when performing this operation on a 45-minute .mpg, the audio is
out of sync by about 3 seconds by the end of the movie.
So, my question is: 'Is there any practical way to specify a lower
bit-rate at the initial rendering from Cinelerra?' (And, if the answer
involves 2-pass processing, then 'What are the tricks to setting that
up?')
At present, my workflow looks like this:
(1) Assemble a movie (to become a dvd 'chapter') in Cinelerra.
(2) From Cinelerra, render video to foo.m2v (YUV4MPEG Stream, using
pipe: 'ffmpeg -f yuv4mpegpipe -i - -y -target ntsc-dvd %'), and audio to
foo.ac3.
(4) From command line: 'ffmpeg -i foo.ac3 -i foo.m2v -target ntsc-dvd
foo.mpg
(5) Then reduce the bit-rate (to, say, 2000kb/s):
ffmpeg -i foo.mpg -pass 1 -passlogfile foo-log -target ntsc-dvd -b
2000k foo-output_pass1.mpg
ffmpeg -i foo.mpg -pass 2 -passlogfile foo-log -target ntsc-dvd -b
2000k foo-output_pass2.mpg
What I find is that the original 'foo.mpg' maintains sync, but the new
'foo-output_pass2.mpg' is out of sync (audio coming earlier) by about 20
minutes into the movie.
Now, should the bit-rate-reduction scheme work if I (a) supply a -b
parameter in the pipe command (within Cinelerra)? or (b) try to specify
2-pass processing?
Thanks again!
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