The VideoLAN Forums

Hello,

I've recently installed VLC player (0.8.1 or 0.8.4.fbx-1 ) on an rather old machine PIII 500 Mhz running W98 SE (4.10 build 2222 with all the updates), Direct X 9.0c build 4.09.0000.0904, 3DFX Voodoo 3AGP video card and I have a lot of freezes ( 'image skip' ?) when playing DVDs.

I'm surprised as I used to watch DVD on this PC with simple DVD player like old version of Ravisent (2.0.0.1001 dated 1999) without any problem.
With the Ravisent player the CPU usage is 35 to 50% while with VLC it is around 100%, which is certainly the problem. I've tried out several video preference adjustments, but only for the worse. Does somebody have any idea ? Did I miss obvious setup adjustments ? My DVD reader is DMA enabled.

Thanks a lot for any help,
Best regards,

J. Marie

Here is a sample of the VLC messages:

main warning: late picture skipped (-9167)
main warning: late picture skipped (5114)
main debug: decoded 81/108 pictures
main warning: late picture skipped (-13667)
main warning: late picture skipped (231501)
main warning: late picture skipped (172078)
main debug: decoded 69/108 pictures
main warning: late picture skipped (5333)
main warning: PTS is out of range (-30588), dropping buffer
main warning: late picture skipped (18867)
main warning: computed PTS is out of range (148123), clearing out
main warning: PTS is out of range (114412), dropping buffer
main warning: output PTS is out of range (184040), clearing out
main warning: PTS is out of range (82412), dropping buffer
main warning: PTS is out of range (55412), dropping buffer
main warning: PTS is out of range (29412), dropping buffer
main warning: late picture skipped (116078)
main warning: PTS is out of range (4412), dropping buffer
main warning: PTS is out of range (-27588), dropping buffer
main warning: late picture skipped (44614)
main warning: late picture skipped (11833)

I don't know your answer but I have a related question.

Why does my CPU usage always read zero percent, even with kernel view enabled? This is a dual Athlon Win2k system with a GeForce 6800 card running VLC 0.8.2. When I use other DVD players such as WinDVD, I see somewhere around 20 or 30 percent.

Hello,

I've tried more setup, without success so far.
I am just wondering, is it simply possible that, at this point, VLC codecs are just -by far - less optimized than other ones available for Windows. What do you think ?

JMPenet

Your 100% CPU utilization certainly explains the skipping. Try exploring your Voodoo driver settings to see if it has acceleration modes that's aren't enabled. Video overlay support usually makes a huge improvement, because that moves a lot of the processing to the graphics hardware.

One easy way to determine if overlays are working is to grab the movie player window with your mouse and shake it while the movie is playing. If the movie image seems to wobble inside the window frame, then overlays are probably working.

In VLC settings, enable "advanced options", and go into the "Video" section. Make sure "overlay video output" is enabled. Also try the various "video output module" choices.

Oops! It's too easy to accidentally post a message to this forum as "guest", and then I can't edit my post.

My "wobble" technique is not 100% reliable. Another way to determine if video overlays are working is to take a simple Windows screen snapshot (press Print Screen) and paste it into something like Photoshop. If VLC's movie window appears almost black, then the video overlay is enabled.

Curiously, when I enable video overlays on my system, I see a big improvement in CPU utilization in some other DVD players, but VLC runs close to 0% either way. Different DVD players probably use different video acceleration techniques, so overall performance probably depends on what features your graphics card supports.

Hello,

I already tried several of your suggestions (on both my graphic card and VLC setup) without success. While some setups are worse than other, none of them allowed a smooth display. I still don't understand why VLC uses 100% of the CPU (in all the setup I tried) while my old reader uses only 35 to 50%. This is obviously the cause of my having problems with VLC. After several hours of trials, I'm reaching the conclusion that, in my specific environment, the VLC codecs are much less efficient that the 'regular' codecs on my PC. Did other with similar configuration experience the same problem ? Is there around a VLC developer to give his/her opinion ?

Thanks and best regards.

JMPenet

Try shrinking your VLC movie window to postage stamp size. Does that significantly improve CPU utilization? If yes, then your graphics hardware acceleration isn't being used.

Try Audio -> Audio Track -> Disable.
Try Video -> Video Track -> Disable.

What's their affect on CPU utilization?

The developers hang out on IRC. Maybe they wouldn't mind answering your technical question if you keep it brief. Info here:
http://developers.videolan.org/vlc/

Also, look at your VLC debug messages when you start playing the disc. Especially this line:
vout_directx debug: DirectDraw Capabilities: overlay=1 yuvoverlay=1 can_deinterlace_overlay=1 colorkey=1 stretch=1 bltfourcc=1

Thank you for your suggestions. Here are the results.

Try shrinking your VLC movie window to postage stamp size. Does that significantly improve CPU utilization? If yes, then your graphics hardware acceleration isn't being used.

I've tried this and the CPU usage doesn't drop significantely below 100%

Try Audio -> Audio Track -> Disable.
Try Video -> Video Track -> Disable.

What's their affect on CPU utilization?

When I disable Video the CPU usage drops to about 50%
It doesn't drop significantely when I disable Audio

Also, look at your VLC debug messages when you start playing the disc. Especially this line:
vout_directx debug: DirectDraw Capabilities: overlay=1 yuvoverlay=1 can_deinterlace_overlay=1 colorkey=1 stretch=1 bltfourcc=1

I have exactly this line in the VLC messages window.

During my trial I've changed the setup of my graphic card and when I display DVD using the old Ravisent DVD player the CPU usage is now down to around 25 %.
I still don't understand this huge CPU usage difference between the VLC player and my old Ravisent player.......
I am still under the impression that VLC player is not optimized yet (at least in my old 98 SE PIII 500Mhz setup)...... Or am I still missing the obvious ?

Thanks,

JM Penet

You disabled audio and video, and it's still chewing up 50% CPU? And your drive's DMA is really working? Ok, I'm stumped too!

Maybe there's a clue in another one of your debug messages, but I don't know what most of them mean.

I used the Ravisent player on my old Win95 box. I recall it was more efficient than the other players.