tcprobe -i anyoldDVfile.avi
>
> Seems you are using transcode ?
>
> Have you ever thought about using the mjpeg tools direct with the
> smilutils (I think they are called that name).
Actually I do :-) but I also have transcode around and tend to occasionaly use
bits of it.
My vhs PAL to SVCD is roughly as follows (inside a perl script) :
smil2yuv -i raw -a audio.mp2 edit.smil | yuvdenoise -F -f | yuvscaler -v O
-O SVCD -n p | mpeg2enc -v 0 -a 2 -f 5 -q 8 -4 2 -2 1 -I 0 -S 795 -B 224 -N
-V 230 -o video.mp2
mplex -v 1 -V -f 5 -m 2 -b 230 audio.mp2 video.mp2 -o out%02d.mpg
ALAS, I've noticed that with long clips the audio gets out of sync. Only
slightly behind the video although it starts out in sync. I'm still puzzled
by it but my best guess is the clock controlling the audio bit rate in my
camcorder is running slightly slow compared to the video bitrate. Playing
back from Digital8 tape or A/V->DV passthrough isn't a problem but capture to
disc is.
I'm still not sure what is going on but have two thoughts - persuade dvgrab to
drop a frame every so often or stretch the mp2 file to the same length as the
m2v prior to multiplexing. I'm not sure on how best to do the latter.
Any comments most welcome :}
Michael.
P.S. In support of my theory running tcscan on a DV produces:
(0x078386f4) ID:<00db> Size: 0x00023280 144000
(0x0785b97c) ID:<01wb> Size: 0x00001e00 7680
(0x0785d784) ID:<00db> Size: 0x00023280 144000
(0x07880a0c) ID:<01wb> Size: 0x00001e00 7680
(0x07882814) ID:<00db> Size: 0x00023280 144000
(0x078a5a9c) ID:<01wb> Size: 0x00001dfc 7676
repeated ad nauseum...
This gives an audio bit rate of 1.53573e+06 whereas 48000*16*2 is 1.536e+06
Only a 0.018% error but over an hour thats around 630 milliseconds
P.P.S. I also notice at the start of a multifile capture the very first file
has slightly more bits dropped in the first few frames e.g. :-
List Type = <movi>
(0x00000800) ID:<00db> Size: 0x00023280 144000
(0x00023a88) ID:<01wb> Size: 0x00001dfc 7676
(0x0002588c) ID:<00db> Size: 0x00023280 144000
(0x00048b14) ID:<01wb> Size: 0x00001dfc 7676
(0x0004a918) ID:<00db> Size: 0x00023280 144000
(0x0006dba0) ID:<01wb> Size: 0x00001dfc 7676
(0x0006f9a4) ID:<00db> Size: 0x00023280 144000
(0x00092c2c) ID:<01wb> Size: 0x00001e00 7680
(0x00094a34) ID:<00db> Size: 0x00023280 144000
(0x000b7cbc) ID:<01wb> Size: 0x00001dfc 7676
(0x000b9ac0) ID:<00db> Size: 0x00023280 144000
etc for around 20-30 frames
but not subsequent files. Now this is simply turning on capture with A/V->DV
there's no moving parts to get up to speed.
So alternative theory 7680 bits per frame are leaving the camcorder but not
making it to the file.
(I'm going to crosspost part of this to the kino list since dvgrab is involved
and they may have comments)
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