Flash audio/video out of sync [Solved]

alienjon · Veteran Joined: 09 Feb 2005 Posts: 1709

Thank you, katkaif. You're input was helpful. I found the level of detail to be of the most assistance, but the link was absolutely invaluable. Should I ever have a problem with my computer again I plan on PM'ing you directly. I wish to name my first born after you.

In other words... {bump}?

[Update]
Well, the katkaif reference made more sense when there was the spam post before it. Oh well :p

myceliv · Apprentice Joined: 29 Nov 2007 Posts: 178

Hmm since no real responses I'll toss out some ideas even though really don't know what might be causing this. Sorry to not provide more detailed support for these ideas.

I have had great results with *not using the lib32 flag on flash. Might try that. Also I thought for amd64 the win32 stuff doesn't get used anywhere. At least it seems to be masked everywhere in my profile (10.0/desktop). So might try without that.

Also there are several kernel settings regarding timers and clocks that could affect audio I think. Perhaps recheck that your kernel timer and alsa settings make sense.

alienjon · Veteran Joined: 09 Feb 2005 Posts: 1709

I was using firefox 32bit binary (I think because at the time flash was only 32 bit, so I needed the binary) With the 64bit binary now, however, I just installed mozilla-firefox-3.5.4 (the latest stable in portage) and though flash works, firefox crashes with a segfault before I can test the audio/video. Also, there's lots of:

alienjon · Veteran Joined: 09 Feb 2005 Posts: 1709

Ok, so - as I mentioned - I installed 64bit firefox and tried using 64bit adobe-flash, but firefox kept crashing on me. It would happen at weird times in several sites (some with flash - such as Hulu and Youtube, but some did not, it crased in gmail for me several times). To make a long story short, I decided to try using the 64bit browser but ndiswrapper with the 32bit plugin. Now it won't crash, but I'm not surprised to see that the audio/video is, again, out of sync. myceliv, you may be right with this being a more generic kernel-wide thing. What, specifically, do you mean by 'timers' that you think I could look into that might be related to all of this?

Audio does work fine with playing regular videos, so I think it is just with adobe-flash, but still I think it's an avenue worth pursuing.

myceliv · Apprentice Joined: 29 Nov 2007 Posts: 178

Ugh, I feel like a third grader asked to step in and teach the fifth grade math class while the teacher's out sick. If your audio is generally ok and it's just flash I doubt kernel settings are part of it. If you want to pursue that I'd just follow the Pappy's Kernel Seeds process. Unless you did weird changes to settings making your kernel this is unlikely to be the problem anyway. Regarding a couple of the issues I do have a little to add though:

XID collision -- as best I can tell this has been occuring with flash for much longer than warnings have been visible to users. It's just been made visible in recent gtk+ since developers enabled the warning. Most everyone ignores it with no bad effects. See this thread for more details.

Disclaimer regarding this next bit: I thought that this was prevented in gentoo, at least the gnutls related part. See closed bug #272388, however I'll link it anyway so you can at least rule out that your processor doesn't match, and you're on a recent gnutls, etc.

Flash segfaults -- there is on archlinux forums a thread that for certain cpus not supporting certain instructions flash crashes on some sites (and looks like people mention sync problems too). Looks like family 15 processors are the problem ones, although at least one person said BIOS version may play a role too. This may be your problem if, e.g.:

alienjon · Veteran Joined: 09 Feb 2005 Posts: 1709

alienjon · Veteran Joined: 09 Feb 2005 Posts: 1709

Thanks for the links, myceliv. There was a post in the archlinux forums that solved the problem (the ironic thing is that the post that helped me included a reference back to Gentoo via a bug post). Basically, the problem is that family 15 processors (AMD64, being one of them) lack the lahf instruction. Someone (Maks Verver, I believe) wrote a hack in the form of code that, when compiled, acts as a plugin for the browser that emulates the lahf instruction. He can explain it much better than I can so I'll defer further explanation to the bug report.

The bottom line is that I'm now not only using 64bit firefox, but also the 64bit flash plugin without any crashing! (So far, at least

) The added bonus is that once I fixed the 64bit plugin, the audio and video synced up! I'm guessing the original problem was related to a 32bit plugin in a 64bit environment (wouldn't have been the browser, since I started with the 32bit binary version).

Thanks for the help!