Log in

View Full Version : Believe it or not! The choice of the MP3 decoder can improve video playback quality!

Awatef
14th October 2006, 11:13
I don't know if many of you already noticed this, but I think it is worth mentioning.
I'm very sensible to stutters and I noticed that using the standard windows MP3 decoder can cause some files to have "wobbling" playback. And then I changed to ffdshow/mp3lib, and see there, no "wobbles" anymore!

Worth a try if you always wondered what can be done to avoid the "wobbles"... :sly:
check
14th October 2006, 11:24
did you use the same player both times? which player? I have never seen this before, are you positive the decoder is the cause?
Awatef
14th October 2006, 16:25
Yes, I used the same player (ZoomPlayer).
But it has the same effect on Windows Media Player too.

I may also add that I am on an LCD display working @ 60Hz, if that matters (hardly?!)
The files I worked on are 23.976fps. IVTC was perfect. The thing is, one file was with VBR MP3, the other with CBR MP3. Strange enough, the file with VBR was perfectly smooth, the one with CBR was giving me the creeps during pans (you know, slightly irregular intervals between the frames, instead of regular intervals).
Now, I don't know if it is a matter of the encoder choice, or the encoding mode, but one thing is sure: the choice of the MP3 decoder used fixed the slight stuttering.
check
14th October 2006, 16:29
I'd like to ask you to confirm this in graphedit - this is an extremely unlikely situation. Are you sure you don't have CPU % problems or similar? Please post screenshots of the different graphs graphedit creates too.
Awatef
14th October 2006, 22:02
Graphedit?! How do you use this?

It can't be a CPU issue, the load is under 30% in both cases.
The slight stuttering is not due to CPU overload, it's just about the way the video is played back. There are no out-of-synch issues or something.
It's just that the pans are not very regular with the standard MP3 decoder... kinda jumpy... (very slightly)
check
15th October 2006, 03:27
Open the file with this: http://cccp.project357.com/index.php?dir=utilities/&file=graphedit051209.zip using the two different decoders, confirm the problem exists when pressing play, and then upload a screenshot of the different filter-chains so we can see :)
Awatef
15th October 2006, 20:56
As you can see, the graphs are the same, it is just the decoder that changes:

http://img130.imageshack.us/img130/732/ffdshowtw8.th.gif (http://img130.imageshack.us/my.php?image=ffdshowtw8.gif) http://img529.imageshack.us/img529/8629/windowsmp3jw9.th.gif (http://img529.imageshack.us/my.php?image=windowsmp3jw9.gif)


Note that there are files that play fine with the standard MP3 decoder. So it probably depends on the encoder used.
Anyway, the thing is, with the files that show the "wobbles", it may be a good idea to change the MP3 decoder :)