[MPlayer-users] slightly confused by mencoder output

[The Eye]

I was using mencoder to record something off of the TV-card a few days
ago. The output had me kinda puzzled. The commandline was:

/usr/local/bin/mencoder -quiet tv:// -tv
driver=v4l2:device=/dev/v4l/video0:width=720:height=530:amode=1:adevice=/dev/dsp1
-oac lavc -ovc lavc -lavcopts acodec=mp2:vcodec=mpeg2video:vbitrate=4000
-vf crop=688:518:16:6,pp=fd -o /some/path/file.avi -endpos 40:00


the output was the following:

MEncoder dev-CVS-050906-22:00-3.4.4 (C) 2000-2005 MPlayer Team
CPU: Advanced Micro Devices Athlon 4 /Athlon MP/XP Palomino (Family: 6,
Stepping: 2)
Detected cache-line size is 64 bytes
CPUflags: Type: 6 MMX: 1 MMX2: 1 3DNow: 1 3DNow2: 1 SSE: 1 SSE2: 0
Compiled for x86 CPU with extensions: MMX MMX2 3DNow 3DNowEx SSE

File not found: 'frameno.avi'
Failed to open frameno.avi
success: format: 9  data: 0x0 - 0x0
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: AverMedia M156 / Medion 2819
 Tuner cap: STEREO LANG1 LANG2
 Tuner rxs: MONO
 Capabilites:  video capture  video overlay  VBI capture device tuner  
read/write  streaming
 supported norms: 0 = PAL; 1 = PAL-BG; 2 = PAL-I; 3 = PAL-DK; 4 =
NTSC; 5 = SECAM; 6 = PAL-M; 7 = PAL-Nc; 8 = PAL-60;
 inputs: 0 = Television; 1 = Composite1; 2 = Composite2; 3 = S-Video;
 Current input: 0
 Current format: BGR24
v4l2: current audio mode is : STEREO
audio block size too low, setting to 16384!
[V] filefmt:9  fourcc:0x30323449  size:720x530  fps:25.00 ftime:=0.0400
==========================================================================
Opening audio decoder: [pcm] Uncompressed PCM audio decoder
AUDIO: 44100 Hz, 2 ch, s16le, 1411.2 kbit/100.00% (ratio: 176400->176400)
Selected audio codec: [pcm] afm:pcm (Uncompressed PCM)
==========================================================================
Opening video filter: [expand osd=1]
Expand: -1 x -1, -1 ; -1, osd: 1, aspect: 0.000000, round: 1
Opening video filter: [pp=fd]
Opening video filter: [crop w=688 h=518 x=16 y=6]
Crop: 688 x 518, 16 ; 6
==========================================================================
Opening video decoder: [raw] RAW Uncompressed Video
VDec: vo config request - 720 x 530 (preferred csp: Planar I420)
[PP] Using external postprocessing filter, max q = 6.
VDec: using Planar I420 as output csp (no 0)
Movie-Aspect is undefined - no prescaling applied.
videocodec: libavcodec (688x518 fourcc=3267706d [mpg2])
Selected video codec: [rawi420] vfm:raw (RAW I420)
==========================================================================
Building audio filter chain for 44100Hz/2ch/s16le -> 0Hz/0ch/??...
Building audio filter chain for 44100Hz/2ch/s16le -> 44100Hz/2ch/s16le...
Writing AVI header...
ODML: Aspect information not (yet?) available or unspecified, not writing 
vprp header.
Forcing audio preload to 0, max pts correction to 0
ODML: Aspect information not (yet?) available or unspecified, not writing 
vprp header.
ODML: Starting new RIFF chunk at 1023MB.

Flushing video frames

Writing AVI index...
Fixing AVI header...
ODML: Aspect information not (yet?) available or unspecified, not writing 
vprp header.

Video stream: 3997.843 kbit/s  (499730 B/s)  size: 1199372783 bytes  2400.040 
secs  59970 frames

Audio stream:  224.175 kbit/s  (28021 B/s)  size: 67252497 bytes  2400.000 secs
v4l2: 60027 frames successfully processed, -6 frames dropped.




now, what I'm confused about is a: why the 2 "Building audio filter
chain" lines? b: Why the two "ODML: Aspect information ..." lines?
They appeared right after each other.

And what does a negative number of dropped frames mean?


When I play the resulting video, the following lines appear in the
output:

AVI: ODML: Building odml index (2 superindexchunks)
VIDEO:  [mpg2]  688x518  24bpp  25.000 fps  3997.8 kbps (488.0 kbyte/s)
VIDEO:  [mpg2]  688x518  24bpp  25.000 fps  3997.8 kbps (488.0 kbyte/s)
VIDEO:  MPEG2  688x518  (aspect 1)  25.000 fps  3997.8 kbps (499.7
kbyte/s)

That looks strange to me as well, why the two identical lines?

And while the file is running, over the course of 40 minutes, the audio
drifts _considerably_ away from the video. Looks like more than a second
near the end.

What, exactly, am I doing wrong?

What I want to accomplish is: Record a big-file high-quality file off of
the tv-card for one-time-viewing, which, if the recording is worth it,
can later be re-encoded with mpeg4 to a smaller size.


-- 
Michael Hellwig  aka  The Eye                 olymp.idle.at admin
check out http://homepage.uibk.ac.at/~csaa5128 for gpg public key
        and don't hesitate to look at http://laerm.or.at


-- 
Michael Hellwig  aka  The Eye                 olymp.idle.at admin
check out http://homepage.uibk.ac.at/~csaa5128 for gpg public key
        and don't hesitate to look at http://laerm.or.at