On Sunday 27 August 2006 03:38, Cyrus A wrote:
> Here is my experience trying to encode into MPEG-4 on the fly while
> also recording closed captions on a PVR-250.
>
> First I tried 'cat /dev/video0 > outputfile.mpg' to get the hardware
> MPEG-2. That worked perfectly.
>
> Then I had some trouble encoding on the fly with ffmpeg. The audio
> was out of sync for some unknown reason. After a couple of days, I
> found that '-async 1' solved my problem. My ffmpeg command is '
> ffmpeg -i /dev/video0 -async 1 -s 480x384 -b 1750 outfile.mpg' I have
> thoroughly tested it and it works well for long periods of time
> (recording an hourlong show, for instance). Now onto closed
> captioning.
>
> zvbi-ntsc-cc doesn't work. I think the program "drives" the video
> device at the same time the drivers are trying to "drive" the device
> and it causes conflicts. This results in choppy, unusable video. The
> same thing happened with bttv.
>
> Then I tried the $ivtvhome/test/vbi program and VIOLA, I got the
> captions I needed and the video was unaffected.... or so I thought...
>
> After a short period, errors start showing up in the video encoding
> terminal:
>
> [mpeg2video @ 0x2aaaab031030]00 motion_type at 12 5=2091.2kbits/s
> [mpeg2video @ 0x2aaaab031030]Warning MVs not available
> [mpeg2video @ 0x2aaaab031030]concealing 1125 DC, 1125 AC, 1125 MV
> errors [mpeg2video @ 0x2aaaab031030]00 motion_type at 33
> 11=2077.1kbits/s [mpeg2video @ 0x2aaaab031030]mb incr damaged
> [mpeg2video @ 0x2aaaab031030]mb incr damaged
> [mpeg2video @ 0x2aaaab031030]mb incr damaged
> [mpeg2video @ 0x2aaaab031030]mb incr damaged
> [mpeg2video @ 0x2aaaab031030]slice mismatch
> [mpeg2video @ 0x2aaaab031030]slice mismatch
> [mpeg2video @ 0x2aaaab031030]slice mismatch
> [mpeg2video @ 0x2aaaab031030]slice mismatch
> [mpeg2video @ 0x2aaaab031030]00 motion_type at 0 20
> [mpeg2video @ 0x2aaaab031030]invalid cbp at 11 21
> [mpeg2video @ 0x2aaaab031030]00 motion_type at 0 22
> [mpeg2video @ 0x2aaaab031030]mb incr damaged
> [mpeg2video @ 0x2aaaab031030]00 motion_type at 0 24
> [mpeg2video @ 0x2aaaab031030]slice mismatch
> [mpeg2video @ 0x2aaaab031030]mb incr damaged
> [mpeg2video @ 0x2aaaab031030]00 motion_type at 1 27
> [mpeg2video @ 0x2aaaab031030]00 motion_type at 0 28
> [mpeg2video @ 0x2aaaab031030]00 motion_type at 0 29
> [mpeg2video @ 0x2aaaab031030]concealing 855 DC, 855 AC, 855 MV errors
> [mpeg2video @ 0x2aaaab031030]00 motion_type at 19 22=2087.8kbits/s
> [mpeg2video @ 0x2aaaab031030]invalid mb type in B Frame at 13 23
> [mpeg2video @ 0x2aaaab031030]mb incr damaged
> [mpeg2video @ 0x2aaaab031030]00 motion_type at 7 25
> [mpeg2video @ 0x2aaaab031030]00 motion_type at 3 26
> [mpeg2video @ 0x2aaaab031030]00 motion_type at 1 27
> [mpeg2video @ 0x2aaaab031030]00 motion_type at 1 28
> [mpeg2video @ 0x2aaaab031030]00 motion_type at 4 29
> [mpeg2video @ 0x2aaaab031030]Warning MVs not available
> [mpeg2video @ 0x2aaaab031030]concealing 360 DC, 360 AC, 360 MV errors
> [mpeg2video @ 0x2aaaab031030]00 motion_type at 1 12e=2086.9kbits/s
> [mpeg2video @ 0x2aaaab031030]00 motion_type at 1 13
> [mpeg2video @ 0x2aaaab031030]slice mismatch
> [mpeg2video @ 0x2aaaab031030]00 motion_type at 6 15
> [mpeg2video @ 0x2aaaab031030]00 motion_type at 1 16
> [mpeg2video @ 0x2aaaab031030]00 motion_type at 13 17
> [mpeg2video @ 0x2aaaab031030]ac-tex damaged at 1 18
> [mpeg2video @ 0x2aaaab031030]invalid mb type in B Frame at 34 19
> [mpeg2video @ 0x2aaaab031030]invalid cbp at 8 20
> [mpeg2video @ 0x2aaaab031030]slice mismatch
> [mpeg2video @ 0x2aaaab031030]00 motion_type at 3 22
> [mpeg2video @ 0x2aaaab031030]00 motion_type at 27 23
> [mpeg2video @ 0x2aaaab031030]00 motion_type at 16 24
> [mpeg2video @ 0x2aaaab031030]mb incr damaged
> [mpeg2video @ 0x2aaaab031030]00 motion_type at 28 26
> [mpeg2video @ 0x2aaaab031030]ac-tex damaged at 4 27
> [mpeg2video @ 0x2aaaab031030]invalid mb type in B Frame at 3 28
> [mpeg2video @ 0x2aaaab031030]mb incr damaged
> [mpeg2video @ 0x2aaaab031030]Warning MVs not available
> [mpeg2video @ 0x2aaaab031030]concealing 810 DC, 810 AC, 810 MV errors
>
> Normally I would just ignore the errors, but they corresponded with
> an audio desyncing from the video. The more errors appeared, the more
> the audio became de-synced from the video.
>
> If anyone can provide any insight, it would be greatly appreciated.
Are you embedding the VBI data into the stream (using the ivtvctl -x1
option) or just reading the VBI data as a separate stream with the vbi
tool?
Please also give the INIT IVTV messages from the kernel log. Also check
the log for any other errors that it may have printed during capturing.
What command(s) do you use to get these results?
Hans
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