All video playing half speed?!

[MJ Peg]

(new thread because it's more general than the previous AVCHD one)

All videos of all types are playing back slowly on my PC! It used to play MOV files (640p 30fps) fine, but now it doesn't - a 13.5 secs video takes 27s to play through - whether it's WMP, MPC or VLC. Same goes for my AVCHD mts files which render OK in MPC apart from the halfspeed problem.

It even affects FLV files, wmv, mp4, .movie, you name it. Even small files of the type where someone saw a funny video and emailed it, you know the sort - small res, limited frame rate suitable for email, shouldn't make a PC struggle at all.

I'm baffled. It's as if someone has redefined time itself as far as the PC is concerned!

It used to be OK, and now it isn't, What has changed in the meantime? That's the problem,,, I put loads of stuff on it while I had the luxury of a broadband connection at the office, now I've brought it home I've noticed it's slooooow. The PC itself still feels snappy in operation, drivers are up to date, anti-virus was up to date and found nothing wrong, nothing sapping CPU power in Task Manager which shows both cores active. I'm mystified!

Help!

[jagabo]

Is your clock (system tray) running slow?

[Sartori]

It did it for me years ago , I found it was a damaged codec (I know VLC uses its own) , I had files doing it in MP and MPC which also had its own codecs as well , never worked out why , when I took out the codecs and reinstalled it worked . This is just a note , maybe it might jog an idea on it for you . Other than that , the only idea I can think of is a damaged entry in the registry (that generically deals with video ie to parse them to a video player <- this is a guess by the way) .

I just remembered , it happened to me twice - the other time was because I was running a program (cant recall its name but its available on this site) that locked the video to the audio through its own clock and it just went bonkers . I disabled it and everything worked again .

[MJ Peg]

Thanks for answering,
The clock is keeping time OK.
I will try Linux tonight (I've got it dual booting with Linux Mint) and see how that gets on with video in general. That should hopefully show up whether it's software or hardware at fault

[MJ Peg]

Solved! Turned out to be a network card going ape - turning it off cleared it all up. Thanks for the ffdshow-mt tip - it seems to have cleared a few blocky artifacts here and there.

Troubleshooting....
First I booted in Linux and all video that would play, played ok (didn't have a 264 codec for AVCHD much to my dismay, getting updates onto a net-less Linux PC is a pain and a half). That indicated it was a software problem of some sort, or hardware config.

I wondered if the M-Audio soundcard was fighting the onboard sound somehow, so I bit the bullet and finally got around to verifying whether it worked, scrabbling around with leads, plumbing it into the hifi, getting to know my way around the M-Audio control panel, much fiddling around with Device Manager, Services, and Control Panel before I finally heard something and the M-Audio mixer actually had an effect on what I was hearing...

Distortion! A fuzzy mess of sloooow playback. The right pitch musically, but spread out in time. Something was obviously doing a lot of consistent interruption of affairs.

Over the next hour or two I spent a lot of frustrating time randomly stopping Systray apps, Services that didn't appear to be required (network stuff) and anti-virus stuff (it's not online and won't have new software installed very often that I can't check elsewhere), turned off all auto-update checks, and tried killing a few processes from Task Manager.

Several times the sound magically cleared to perfect, and all video played like a charm. FLV files played as normal, MOV MJPEG files fine with no problems reminiscent of Rolling Shutter, and my 720p25 AVCHD Lite mts files were smooth as silk, as were my AVI conversions from Prism or VirtualDub+ffdshow (after deshaking). So that proved that the hardware was up to the task, much to my relief.

- but several times, after enjoying the awesome clear sound, I thought I'd better reboot to verify that it was sorted and that what I'd done was going to 'stick' next time. Several times I nearly pulled out my hair in frustration!

Finally, after much dogged endeavour, I was idly looking around in Device Manager to see if there was anything I could switch off as a last resort. I happened upon a network card that wasn't really required for this standalone audiovisual workstation, so I disabled it and BAM! - instant clear audio instead of the fuzzy mess. And after a few more reboots I can remain hopeful that it really is solved. The previous times it cleared must have been due to stopping attempts to access the network, so the card could go to sleep?

My only issue now (that I'm aware of so far!) is the good old 16-235 versus 0-255 colourspace issue. VLC plays some nighttime footage (AVCHD/h264) with all the dark areas clearly visible (as does my VideoPad NLE), but MPC and WMP have greater contrast making the dark much blacker. It's a matter of sorting out what is actually correct versus what I prefer even if it's wrong (I like to see dark detail in nice bright pictures) and I need to see what happens when I edit stuff together - will it keep the black levels of the originals or will it brighten/darken? That can wait for another day though, for now I'm exhausted but happy, enjoying music I haven't played for ages which sounds awesome. At one point while fixing a cutting out problem (speaker wire loose) I thought the speaker had disconnected internally as there was no sound audible whatsoever (above the mild PC fan noise) but it turned out the mp3 had stopped playing! That's what I call good S/N ratio!

Thanks everyone.

[jagabo]

Levels shouldn't change with proper handling. Attached is a good levels test chart encoded with MPEG 2. On a properly calibrated display everything below 16 should be perfectly black, everything above 235 should be perfectly white (in a professionally produced DVD there will be no pixels outside the 16-235 range). That is, you should not be able to see any difference between 16 and the shades below it, or between 235 and the shades above it. You should be able to see the difference between all the shades between 15 and 235.

[MJ Peg]

Thanks
I wasn't going to worry if my 'movies' turned out to look like the original clips in both players, but I suppose I'd be better off editing my stuff and seeing it how the rest of the world would
How to make it look correct is the million dollar question... I'll see if turning off ffdshow-mt for h.264 makes any difference first. GSpot reports that ffdshow is likely to be used between AVI splitter and [video renderer] ... but it's a bit of a totally confusing grey area for me, how all that gubbins actually hangs together and what defines what,

[Sartori]

It does make me shake my head at how "rickety" PCs are and if you`re not willing to get your hands dirty or know what question to ask , you end up with an expensive paperweight . Glad its all working again for you , nothing worse than a problem like that .
@jagabo - thanks for those

[MJ Peg]

Thanks, I've moved to a more relevant thread if you'd care to join me there
https://forum.videohelp.com/threads/313178-A-problem-with-dynamic-ranges

Cheers