Otto J. Makela wrote:
For some reason vamps doesn't properly work for me, uses up lots of cpu
cycles (and if running with -v -v produces output) but it just seems to
stop producing output at some point and never actually completes...
My guess is that it sees something in the input stream which causes a problem,
as it always stops at the same byte count on a given file.
% uname -a
Linux tigger.otto.net 2.6.27.12-170.2.5.fc10.x86_64 #1 SMP Wed Jan 21 01:33:24
EST 2009 x86_64 x86_64 x86_64 GNU/Linux
% tcprobe -i Time-2-dvd.mpg
[tcprobe] MPEG program stream (PS)
[tcprobe] summary for Time-2-dvd.mpg, (*) = not default, 0 = not detected
import frame size: -g 720x576 [720x576]
aspect ratio: 16:9 (*)
frame rate: -f 25.000 [25.000] frc=3
PTS=0.1200, frame_time=40 ms, bitrate=7784 kbps
audio track: -a 0 [0] -e 48000,16,2 [48000,16,2] -n 0x50 [0x2000] (*)
PTS=0.1200, bitrate=224 kbps
-D 0 --av_fine_ms 0 (frames & ms) [0] [0]
% date; time vamps -v -v -e 1.22 -a 1 -p -i xx < Time-2-dvd.mpg >
Time-2-shrink-dvd.mpg
Fri Feb 13 14:41:50 EET 2009
Info: Actual video ES vaporization factor: 1.221
Info: Actual video ES vaporization factor: 1.221
Info: Actual video ES vaporization factor: 1.219
...
Info: Actual video ES vaporization factor: 1.233
Info: Actual video ES vaporization factor: 1.203
Info: Actual video ES vaporization factor: 1.217
^C
vamps -v -v -e 1.22 -a 1 -p -i xx < Time-2-dvd.mpg > Time-2-shrink-dvd.mpg
236.15s user 3.69s system 92% cpu 4:18.14 total
% date
Fri Feb 13 14:46:10 EET 2009
% ls -lh Time-2-*
-rw-rw-r-- 1 otto otto 1.5G 2007-07-27 14:43 Time-2-dvd.mpg
-rw-rw-r-- 1 otto otto 20M 2009-02-13 14:42 Time-2-shrink-dvd.mpg
It still seems to work well for me in the circumstances I have
described, but there is lots of code in eg read-cell that seems to be
aimed at reading strange dvd-specific packets.
It does seem, however, that the output file plays for a few seconds less
than the input file. I suspect that the final 4Mb output buffer is not
being written.
This thread *is* still relevant to this list because vamps does
(sometimes!!) a job similar to the suspect, and deprecated, tcrequant.
I'm sure content providers must use something like this to tailor their
transmissions to fit their channel bandwidth: or is it all done in hardware?
John P
