Does anybody have any suggestions to what I can do about duplicated
frames I get when I capture from TV? It's bad enough that there isn't
much point in capturing at all.
I can find almost nothing about this problem on the net, but I gather
that it may have to do with audio (capture? transfer?) being too
slow, so the capture software duplicates frames to keep things in
sync.
Captures without sound don't seem to have problem either.
There's no discernible pattern to when the duplicate frames happen;
it can be right at the beginning or later on and sometimes a stream
of them right after each other and sometimes just one once in a while.
My system:
Kernel 2.4.20 with rml preempt patches.
Debian testing/unstable.
Athlon XP 1800+.
K7S5A motherboard (SIS735).
256mb. PC133 RAM.
SB Live! Player 1024 (emu10k1 kernel driver).
Pinnacle PCTV Rave (bt878, mt2032 tuner).
Capturing to a 30gb. IBM DTLA-307030 (in UDMA100 mode).
bttv-0.9.4 (w/gbuffers=32).
I usually capture in 384x288, 25 FPS (from a PAL source),
using framecopy for sound.
CPU load is usually between 25 and 35% when capturing.
# cat /proc/modules
agpgart 13536 3 (autoclean)
it87 7136 0
i2c-proc 6592 0 [it87]
i2c-isa 1220 0 (unused)
tuner 9572 1 (autoclean)
tvaudio 11904 0 (autoclean) (unused)
tda9887 3104 1 (autoclean)
bttv 77536 0
video-buf 9568 0 [bttv]
i2c-algo-bit 7820 1 [bttv]
i2c-core 14912 0 [it87 i2c-proc i2c-isa tuner tvaudio tda9887
bttv i2c-algo-bit]
v4l2-common 2624 0 [bttv]
videodev 5664 2 [bttv]
nvidia 1467680 10
(just in case that tells anybody anything...).
I have so far used mencoder (from the mplayer package) to capture
with, but streamer also creates duplicate frames (lavrec caused
the first hard lockup I've had in two years or so, so even if it
sounds interesting I'm not too keen on trying it again).
Captures made with the rather awful Pinnacle OEM software on
Windows don't show the problems (only eyeball tests because
the Linux encoders don't like the Pinnacle codec, but I captured
most of Aliens and didn't see anything fishy).
-R.
