[MPlayer-users] What is diff_time? (A/V sync probs)

[Christopher J. Bottaro]

After mencoder finishes encoding an XVID, it prints this out:

---
Flushing video frames

CBR audio: 12000 bytes/sec, 313 bytes/block

Writing AVI index...
Fixing AVI header...
ODML: vprp aspect is 16384:13107.

Video stream:  172.076 kbit/s  (21509 bps)  size: 28673525 bytes  1333.066
secs                      32059 frames

Audio stream:   96.000 kbit/s  (11999 bps)  size: 16002914 bytes  1333.577
secs
diff_time: 0.531, merge_time: 0.268, export: 18634, merge: 30, copy: 1299
---

Why is the video stream 0.511 secs shorter than the audio stream?  What does
'diff_time: 0.531' mean?  I tried delaying the audio (or video?) by .500 ms
and it _seemed_ to make the A/V more in sync (its hard for me to tell these
things).

Here is the mencoder command line that I'm using:

mencoder -dvd-device /media/cdrecorder dvd://5 -o test.avi -ovc xvid
-xvidencopts bitrate=256:max_bframes=0 -oac mp3lame -lameopts
mode=2:cbr:br=96 -vf
filmdint=io=2997:1400,scale=160:120,expand=160:128,harddup -af
volnorm,resample=44100 -ofps 14.985 -srate 44100 -aid 128

Thank you for the help.