[MPlayer-users] Strange timecode behavior with FLAC files

Daniel Dawson ddawson at icehouse.net
Thu May 13 11:01:29 CEST 2010

Greetings. I've noticed that MPlayer's idea of the current time in FLAC
files is strange. It tends to be inaccurate, at least for me. What I
have observed:

* The timecode starts out stuck at some non-zero value and "flickers"
  around very close to it. Once the playback gets to that time, the
  timecode starts moving forward in almost a normal way. If I seek back
  to the beginning, it does the same thing over again.
* The timecode tends to drift a bit ahead of the true time over the
  course of playback, usually by several seconds.
* Sometimes, the timecode will jump back a bit. My investigations
  suggest this is associated with runs of (near-)silence in the audio.

Also, if there is silence (as in the signal is exactly zero or *very*
close) at the end, the playback cuts off at the beginning of it.
Fortunately, the sound output is otherwise fine.

For anyone who's interested, I made a video closely comparing plyback of
an LPCM WAV and a FLAC of the same audio, viewable at
http://www.youtube.com/watch?v=AATVfWarLY0 . The video itself has no
audio with it; it just shows the command-line status display. There's a
lot of variability in behavior across different files, but what you can
see there is typical.

To be fair, I see problems with FLAC in other applications. For
instance, I'm only getting mono output in XMMS2. Another application
replaces small chunks of audio with bursts of noise. In other words,
maybe FLAC is just problematic for direct playback. Is this the case?


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