mpegplayer A/V sync - please report experiences

[linuxstb]

I've just committed some improvements to the A/V sync in mpegplayer.  It seems to be working for my streams, but it would be useful to get feedback (good or bad) from more people.

Note that for mpegplayer to even attempt to play a video in sync with the audio, you MUST enable both the Limit FPS and Skip Frames options in mpegplayer.

Also, before reporting any problems, please test the video on a desktop video player and make sure it is playing in sync there - to rule out any encoding issues.

[Mad Cow]

Video and audio were in sync for me right after the first commit, so I can't comment on this one.

[Nate!]

Worked for me after the first sync also.  Although, I probably should test on a movie that's filmed in my native language.  Watching House of Flying daggers with english voice over probably isn't a good idea.   Just Joking around.  I'll try with an updated build and appropriate movie.  

[mannequin]

all the videos that had slight sync problems before the improvements are perfectly OK for me now. again, thanks a lot, linuxstb. it's truly amazing seeing the gigabeat kicking the video.

[pabouk]

On iriver H120 the picture is slower than the sound. After one minute of playback the picture was several seconds behind the sound. Tested on Elephants Dream, 176x128-310kbps.

BTW: The framerate on H120 is terribly low Maybe it would be worth to try spatial instead of time dithering for the levels of grey.

[ColdSphinx]

Do you have skipframes enabled?

[devonian69]

I ripped one of my Seinfeld DVDs into an mpeg file and it worked great! I was very impressed with the sync. I honestly had to keep reminding myself to pay attention for it - otherwise I would never have even thought about it.

I am using a Gigabeat F10

[Soader03]

The video is about 1-2 seconds faster than the sound. I have all the options enabled. I use a Gigabeat F10.

[Llorean]

"1-2 seconds faster" meaning it plays 1-2 seconds ahead of the sound all the way through?

And what SVN revision is this with?

[linuxstb]

The video is about 1-2 seconds faster than the sound. I have all the options enabled. I use a Gigabeat F10.

If that happens with current SVN, and the file plays perfectly on your computer, can you upload the file somewhere for me to analyse?

[Soader03]

Um, ok. I'll do an update and try a file. I'll edit this post for the uploaded video.

**EDIT**

http://www.megaupload.com/?d=LSQPSWR0
Well done, the video is here, sorry if it's at Megaupload and it's slow...
Check the guy with the yellow t-shirt signing.

**REEDIT**

I just want to add that this video was synchronized before the synchronization update.

[linuxstb]

Thanks for uploading that file.

It's not easy to tell what the correct a/v sync should be on that video, but comparing mpegplayer with "mplayer" (the video player I use for reference), there is definitely a large difference, so something is wrong with mpegplayer.

Before the AV sync commits, Rockbox would just play the video and audio at the correct speeds without taking into account the timestamps in the file.  mpegplayer now attempts to play the video and audio according to those timestamps, which is where it must be going wrong in your file.

If you (or anyone else) have other videos with similar problems, they would be useful to have as well.

[pabouk]

Do you have skipframes enabled?

Yes, linuxstb described it as a requirement for this test and I think that it is obvious.

In addition the "Show FPS" option does not work on H120. Is it supposed to work on greyscale targets?

[Llorean]

No, due to the way the grayscale library works it won't display.

[Didro]

Have to say that before improvements my quality of video in MpegPlayer on IPOD nano was perfect and A/V sync works wonderfully. But after this it became worse, especially video. So please do feedback.