[MPlayer-users] mencoder mpeg2->divx audio delay question
Steven M. Schultz
sms at 2BSD.COM
Thu Aug 15 19:57:01 CEST 2002
Hi!
I'm having difficulty encoding from YUV4MPEG2 (from a DV file)
to divx. The audio races ahead of the video (the A-V column
gets very large very quickly).
This is not the DV in avi problem because I am feeding mencoder
YUV4MPEG2 data (from lav2yuv) and MP3 audio (from lame).
Here's the script being used:
-----------
#!/bin/sh
N=coalb
lav2wav $N.eli | lame -b 128 - $N.mp3
lav2yuv $N.eli | \
mencoder -vop scale=480:480 -sws 2 \
-oac copy -audiofile $N.mp3 \
-ovc lavc \
-lavcopts vcodec=mpeg4:vbitrate=2500:vhq:vmax_b_frames=4:vpass=1 \
-o $N.divx -- -
lav2yuv $N.eli | \
mencoder -vop scale=480:480 -sws 2 \
-oac copy -audiofile $N.mp3 \
-ovc lavc \
-lavcopts vcodec=mpeg4:vbitrate=2500:vhq:vmax_b_frames=4:vpass=2 \
-o $N.divx -- -
-----------
Playing the output file:
Playing coalb.divx
Detected AVI file format!
VIDEO: [DIVX] 480x480 24bpp 29.97 fps 2632.3 kbps (321.3 kbyte/s)
Detected audio codec: [mp3] afm:1 (mp3lib MPEG layer-2, layer-3)
Opening audio decoder: [mp3lib] MPEG layer-2, layer-3
AUDIO: 48000 Hz, 2 ch, sfmt: 0x10 (2 bps), ratio: 16000->192000 (128.0 kbit)
vo: X11 running at 1600x1200 with depth 24 and 32 bpp (":0.0" => local display)
==========================================================================
Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
Detected video codec: [ffodivx] vfm:5 (FFmpeg MPEG-4)
libavcodec: CPU flags: mmx mmxext sse
==========================================================================
AO: [oss] 48000Hz 2ch Signed 16-bit (Little-Endian)
Start playing...
A: 27.6 V: 0.0 A-V: 27.543 ct: 0.000 1/ 1 0% 0% 0.0% 0 0 0%
A: 27.6 V: 0.1 A-V: 27.538 ct: 0.003 2/ 2 0% 0% 0.0% 0 0 0%
A: 36.8 V: 0.1 A-V: 36.726 ct: 0.007 3/ 3 0% 0% 0.0% 0 0 0%
VDec: vo config request - 480 x 480 (preferred csp: Planar YV12)
Movie-Aspect is undefined - no prescaling applied.
VO: [xv] 480x480 => 480x480 Planar YV12
Disabling DPMS
A: 46.0 V: 0.1 A-V: 45.916 ct: 0.010 4/ 4 0% 0% 0.0% 0 0 0%
A: 64.5 V: 0.2 A-V: 64.307 ct: 0.013 5/ 5 0% 0% 0.0% 0 0 0%
A: 73.7 V: 0.2 A-V: 73.495 ct: 0.017 6/ 6 0% 0% 0.0% 0 0 0%
A: 82.9 V: 0.2 A-V: 82.683 ct: 0.020 7/ 7 0% 0% 0.0% 0 0 0%
A: 92.1 V: 0.3 A-V: 91.872 ct: 0.023 8/ 8 0% 0% 0.0% 0 0 0%
A: 110.6 V: 0.3 A-V:110.253 ct: 0.027 9/ 9 0% 0% 0.0% 0 0 0%
A: 119.8 V: 0.3 A-V:119.441 ct: 0.030 10/ 10 0% 0% 0.0% 0 0 0%
A: 138.2 V: 0.4 A-V:137.822 ct: 0.033 11/ 11 0% 0% 0.0% 0 0 0%
A: 147.4 V: 0.4 A-V:147.011 ct: 0.037 12/ 12 0% 0% 0.0% 0 0 0%
A: 147.4 V: 0.4 A-V:147.007 ct: 0.040 13/ 13 0% 0% 0.0% 0 0 0%
...
Wow, see the A-V column?
The video plays back at what appears to be the correct rate but the
audio is much too fast.
During the encoding everything looks fine - the A-V numbers look
good:
INFO: [lav2yuv] DV frame 13649 len 120000 0mb A-V:0.057 [2480:128]
INFO: [lav2yuv] DV frame 13650 len 120000 0mb A-V:0.060 [2480:128]
INFO: [lav2yuv] DV frame 13651 len 120000 0mb A-V:0.063 [2480:128]
INFO: [lav2yuv] DV frame 13652 len 120000 0mb A-V:0.067 [2480:128]
Where might problem be? In the YUV4MPEG2 handling (DV data is
bottom field first but that shouldn't make a difference)? 48k audio?
Has any one else experimented with encoding DV data (from either a
camcorder or a Canopus ADVC-100 analog->DV converter)? No trouble
producing MPEG-2 (SVCD or DVD format) files. And if I take one of
those MPEG files thru mencoder the .divx file is correct.
Steven Schultz
sms at 2bsd.com
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