VLC 2.0.1 Stuttering, apparently due to .NET4 Updates

[mderouss]

Hi folk,

I started to experience stuttering when playing back my FLAC's today. 2.0.1 has worked fine since it was installed ( 19th May ), today no. System is Windows 7 Professional 64 bit.

From the log file :

main warning: audio output out of sync, adjusting dates (66136 us)
main warning: not synchronized (66137 us), resampling
main warning: buffer way too late (188338), dropping buffer
main warning: audio output out of sync, adjusting dates (66137 us)
main warning: not synchronized (66138 us), resampling
main warning: resampling stopped after 34367439 usec (drift: -156835)
main warning: buffer too late (156835), up-sampling
main warning: audio output out of sync, adjusting dates (68513 us)
main warning: not synchronized (68513 us), resampling
main warning: buffer way too late (222082), dropping buffer
main warning: audio output out of sync, adjusting dates (66137 us)
main warning: not synchronized (66138 us), resampling
main warning: buffer way too late (184660), dropping buffer
main warning: audio output out of sync, adjusting dates (66140 us)
main warning: not synchronized (66141 us), resampling
main warning: audio output out of sync, adjusting dates (60551 us)
main warning: not synchronized (60551 us), resampling
main warning: buffer way too late (183620), dropping buffer

Note the 'buffer way too late, dropping buffer' messages.

I backed out the latest batch of Microsoft updates that I applied today, which related to .NET4 Framework, and the problem went away. The following KB's were backed out ( it was a large update ) :

2656368
2656351
2633870
2604121
2600217
2572078
2539636
2533523
2518870
2478663
2468871
2446708
2160841

Log file now shows no dropped buffers, the 'buffer too late' messages seem to be normal (?) :

main warning: resampling stopped after 23584300 usec (drift: 1349)
main warning: audio output out of sync, adjusting dates (63710 us)
main warning: not synchronized (63710 us), resampling
main warning: buffer too late (62361), up-sampling
main warning: resampling stopped after 22669488 usec (drift: 1130)
main warning: audio output out of sync, adjusting dates (62628 us)
main warning: not synchronized (62629 us), resampling
main warning: buffer too late (61498), up-sampling
main warning: resampling stopped after 22569989 usec (drift: 973)
main warning: audio output out of sync, adjusting dates (62811 us)
main warning: not synchronized (62812 us), resampling
main warning: buffer too late (61839), up-sampling
main warning: resampling stopped after 22570276 usec (drift: 611)
main warning: audio output out of sync, adjusting dates (62583 us)
main warning: not synchronized (62584 us), resampling
main warning: buffer too late (61974), up-sampling
main warning: resampling stopped after 22569938 usec (drift: 498)
main warning: audio output out of sync, adjusting dates (62492 us)
main warning: not synchronized (62493 us), resampling
main warning: buffer too late (61995), up-sampling

How on earth .NET4 updates could influence VLC is yet to occur to me. 'Indirectly' seems like a fair bet. I'm not intending to try chasing down the particular KB myself, at least not right now, getting this far took quite a while . I'm pretty sure the issue does not lie with the top three in the list, as I was checking performance after every KB up til then, but it just got too time consuming.

Hope this helps someone.

Cheers,
Mark

[VLC_help]

VLC doesn't use .NET4 Framework, so only guess I take is that some device driver or other program uses it, and with newer version it takes a bit more CPU time. And that causes VLC to miss sync moments.

[mderouss]

Yeah... but it still doesn't make sense - you can't write a device driver per se in managed code, AFAIK. So if it's application, how does that work ? If it's actually affecting scheduling to the extent of hitting a relatively low bandwidth app like VLC ( i.e. VLC is using less than 1% CPU right now playing a FLAC as I type this ), then it's having a massive effect, and VLC is unlikely to be the only victim. Can't help but think there's still a missing link in this problem somewhere . Of course MSFT could have screwed up. Not impossible .

[mderouss]

Update
======

I used Windows Update to bring back .NET 4 related updates one by one, and tested VLC functioning after each.

I now have all available .NET related updates installed, and VLC is working fine.

BUT - I now appear to have a distinctly different set of updates to what I had previously.

I am now missing :

2633870
2572078
2539636
2518870
2478663
2446708
2160841

Instead of 2656368, I have 2656368v2 .

And I have these new ones :

2686827
2656405

So it looks to me like my .NET 4 Framework updates were screwed, for reasons unknown, and are now fixed, and that this solves my problem. Grrrrrrr.... gotta remember life is too short to find the last bug !