[MEncoder-users] Encoding using mencoder from a TV V4L2 source.

[Craig Kadziolka]

Hi,

Im attempting to record television from a tv capture card under linux. The 
card works fine when using xawtv to watch tv through the card, however when 
I try to encode it on the fly using mencoder and then play it back with 
mplayer I have a problem with an annoying static-type line flickering 
through the picture at random intervals. I definately dont get this flicker 
when im watching tv through xawtv, so my guess is that its not a problem 
with the tv card itself?

I dont have any problems with dropped frames, according to the output from 
mencoder. Perhaps i need to run some sort of filter or something? Does 
anyone have any ideas/advice? I can get more debugging info if necessary.

Regards,

Craig.


This is the command line I use for mencode:

mencoder tv:// -tv 
driver=v4l2:width=576:height=576:device=/dev/video0:immediatemode=0:forceaudio 
 -o out.avi -ovc lavc -lavcopts vcodec=mpeg4:aspect=4/3 -aspect 
4:3 -noautoexpand -oac lavc -endpos 00:00:30

And here is the output after running this:

MEncoder 1.0pre7-3.3.4 (C) 2000-2005 MPlayer Team
CPU: Advanced Micro Devices Athlon Thunderbird (Family: 6, Stepping: 2)
Detected cache-line size is 64 bytes
CPUflags: Type: 6 MMX: 1 MMX2: 1 3DNow: 1 3DNow2: 1 SSE: 0 SSE2: 0
Compiled for x86 CPU with extensions: MMX MMX2 3DNow 3DNowEx

success: format: 9  data: 0x0 - 0x0
TV detected! ;-)
Selected driver: v4l2
 name: Video 4 Linux 2 input
 author: Martin Olschewski <olschewski at zpr.uni-koeln.de>
 comment: first try, more to come ;-)
Selected device: BT878 video (Leadtek WinFast 20
 Tuner cap:
 Tuner rxs: LANG1 LANG2
 Capabilites:  video capture  video overlay  VBI capture device  tuner 
read/write  streaming
 supported norms: 0 = PAL; 1 = NTSC; 2 = SECAM; 3 = PAL-Nc; 4 = PAL-M; 5 = 
PAL-N; 6 = NTSC-JP; 7 = PAL-60;
 inputs: 0 = Television; 1 = Composite1; 2 = S-Video; 3 = Composite3;
 Current input: 0
 Current format: BGR24
v4l2: current audio mode is : LANG1
[V] filefmt:9  fourcc:0x32315659  size:576x576  fps:25.00  ftime:=0.0400
==========================================================================
Opening audio decoder: [pcm] Uncompressed PCM audio decoder
AUDIO: 44100 Hz, 1 ch, s16le, 705.6 kbit/100.00% (ratio: 88200->88200)
Selected audio codec: [pcm] afm:pcm (Uncompressed PCM)
==========================================================================
==========================================================================
Opening video decoder: [raw] RAW Uncompressed Video
VDec: vo config request - 576 x 576 (preferred csp: Planar YV12)
VDec: using Planar YV12 as output csp (no 0)
Movie-Aspect is 1.33:1 - prescaling to correct movie aspect.
videocodec: libavcodec (576x576 fourcc=34504d46 [FMP4])
Selected video codec: [rawyv12] vfm:raw (RAW YV12)
==========================================================================
Building audio filter chain for 44100Hz/1ch/s16le -> 44100Hz/2ch/s16le...
Writing AVI header...
ODML: vprp aspect is 4:3.
ODML: vprp aspect is 4:3.
Pos:   0.0s      1f ( 0%)   0fps Trem:   0min   0mb  A-V:0.000 [0:0]
Pos:   0.1s      2f ( 0%)   0fps Trem:   0min   0mb  A-V:0.000 [0:0]
Pos:   0.1s      3f ( 0%)   0fps Trem:   0min   0mb  A-V:0.000 [0:0]
Pos:   0.2s      4f ( 0%)   0fps Trem:   0min   0mb  A-V:0.000 [0:0]
Pos:   0.2s      5f ( 0%)   0fps Trem:   0min   0mb  A-V:0.000 [0:0]
Pos:   0.2s      6f ( 0%)   0fps Trem:   0min   0mb  A-V:0.000 [0:0]
Pos:   0.3s      7f ( 0%)   0fps Trem:   0min   0mb  A-V:0.000 [0:0]
Pos:   0.3s      8f ( 0%)   0fps Trem:   0min   0mb  A-V:0.000 [0:0]
... pattern continues exactly the same ...
Pos:  29.8s    745f ( 0%)  25fps Trem:   0min   0mb  A-V:0.000 [862:223]
Pos:  29.8s    746f ( 0%)  25fps Trem:   0min   0mb  A-V:0.000 [861:224]
Pos:  29.9s    747f ( 0%)  25fps Trem:   0min   0mb  A-V:0.000 [861:223]
Pos:  29.9s    748f ( 0%)  25fps Trem:   0min   0mb  A-V:0.000 [861:223]
Pos:  30.0s    749f ( 0%)  25fps Trem:   0min   0mb  A-V:0.000 [861:223]
Pos:  30.0s    750f ( 0%)  25fps Trem:   0min   0mb  A-V:0.000 [861:223]
Pos:  30.0s    751f ( 0%)  25fps Trem:   0min   0mb  A-V:0.000 [860:223]

Flushing video frames

Writing AVI index...
Fixing AVI header...
ODML: vprp aspect is 4:3.

Video stream:  860.790 kbit/s  (107598 bps)  size: 3232268 bytes  30.040 
secs  751 frames

Audio stream:  224.000 kbit/s  (27999 bps)  size: 840411 bytes  30.015 secs
v4l2: 754 frames successfully processed, 0 frames dropped. 



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