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any VLC tricks for low power CPU?

Posted: 22 Aug 2011 22:21
by lovelove
Hi, my PC is a bit old already and doesn't have enough CPU power to play high resolution video (which leads to stuttering).

- Can I tell VLC to render the video at half its size so that I can at least watch the video in lower resolution?
- Or in lower quality?
- Or can I tell VLC to drop every second fame, so that there are less fps to calculate?

I guess not, but I still wanted to try asking.

Otherwise .... is there anything else I can do?
Many thanks for any suggestion.

Re: any VLC tricks for low power CPU?

Posted: 22 Aug 2011 22:31
by RĂ©mi Denis-Courmont
In principles, reducing the resolution takes more CPU than keeping the original size, since the CPU must do the scaling. Of course, in practice, it should be irrelevant because most graphic adapters, even the low end ones, can deal with scaling and color space in hardware.

The CPU is thus used mostly for decoding, and a little bit for demultiplexing. There are not many ways to reduce CPU consumption, other than dropping frames. And even that does not really work. At least the key frames need to be fully decoded if there is to be any picture at all. Yet the key frames are the ones that take most computational time...

In other words, you are probably screwed. Make sure you have all fitlers disabled, but probably they are.

Re: any VLC tricks for low power CPU?

Posted: 03 Sep 2011 02:47
by lovelove
Yeah, that's what I feared. Anyway, thank you for the good explanation.
Yet the key frames are the ones that take most computational time...
I thought it would be the opposite ... key frames require biggest file size, but least CPU, while B frames require least file size but most CPU (hence the b-frame limitations or some codecs not using them at all).

After all, key frames don't rely on any other frames to be decoded. They are basically stand-alone images and are just displayed as any other regular single image on your computer. All other frames need prior decoding of the frames they depend on and even after they are decoded, the CPU still has to calculate how the image should look like based on the diff information (motion vectors, etc.)

Re: any VLC tricks for low power CPU?

Posted: 03 Sep 2011 13:40
by Sumoku
Let's face it: on a normal PC with a single-core processor and run-of-the-mill graphics card, VLC cannot cope adequately with most high-definition video sources (720p and above). We'd like it to; we earnestly wish it could ... but it can't. Worse still, even those with multi-core, all-singing, all-dancing systems, with high-end graphics cards and all the latest bells and whistles, have found themselves unable to play various types of HD file with VLC, a program that once upon a time seemed the only truly universal player/streamer/recorder/converter, but which is now showing its age, or perhaps its lack of serious development. (Something went wrong when Version 1.0 was introduced, promising so much and delivering rather less.)

Some dyed-in-the-wool fans of VLC may object to this response, but the truth must be recognized. I, too, am a long-time worshipper of the venerable VLC, but I am now waking up to the ugly reality that it is no longer the unassailable and uncontested world ruler it once was.

Alas, for now at least, the only solution for HD sources seems to be to turn to another player, such as Media Player Classic, or, better still, the newly released JetVideo. Neither of these has the fine-tuning options of VLC, but they can at least play almost all videos, including HD ones, at their full frame-rate, without stuttering or dropping frames or losing video-audio synchronization (a surprising and particularly distressing fault).

MPC will play some files that VLC struggles with, but it, too, has a hard time with some HD sources. JetVideo (freeware) is especially impressive, and, although it's not quite as flexible as VLC, it does allow lots of tweaking, such as cropping, resizing, repositioning, and changing of aspect ratio (alas, with mostly different keyboard hotkeys). The one significant thing it can't do is remove individual horizontal or vertical lines of pixels -- a very useful feature for adjusting those all-pervasive poorly made videos (especially on DVD) with jagged, uneven, or wrongly-coloured edges. Nevertheless, I recommend JetVideo wholeheartedly for HD video sources, which, in any case, generally have clean edges and no unnecessary black borders, and thus need little or no tweaking. Try it, if you haven't already, and you'll thank me.

By the way, I am not recommending that anybody abandon VLC altogether, but rather that we all begin to look elsewhere when VLC proves itself inadequate -- which, alas, seems to be ever more often of late.

PS I have no affiliation with COWON, the makers of JetVideo. I just found it by chance, this very week, and it has not disappointed me yet. Nevertheless, roll on the day that VLC returns as the true and only king!

Re: any VLC tricks for low power CPU?

Posted: 07 Sep 2011 21:29
by mederi
As I also must cope with old computer (P3) I found following setting that help me with higher resolution XVID videos, but doesn't work on H264 (why?):
Tools >> Preferences: Show settings - All >> Input / Codecs >> Video codecs >> FFmpeg: Decoding - Low resolution decoding [2]
-> Save -> restart
For H264 I use following setting in the same section there:
- Skip the loop filter for H.264 decoding [Bidir]

Re: any VLC tricks for low power CPU?

Posted: 26 Jul 2012 07:18
by chefcolby
im not sure if anybody cares anymore but i did the same and downloaded a file that was 720 and it was very choppy, after following mederi's post and then about an hour of my own tricks it still wouldn't work, so rather then try to correct everything i changed i went into tools preferences and hit the little bubble at the bottom of the prompt to reset preferences and it started playing fine, i hadn't changed anything prior to this so i don't know why it didn't work before but apparently some setting was changed somehow.

Re: any VLC tricks for low power CPU?

Posted: 27 Jul 2012 18:46
by Jean-Baptiste Kempf
Using GPU decoding is usually quite helpful, if you can.
Removing all audio resampling too.

Re: any VLC tricks for low power CPU?

Posted: 27 Oct 2012 23:52
by Schweitzer
Nevertheless, I recommend JetVideo wholeheartedly for HD video sources, which, in any case, generally have clean edges and no unnecessary black borders, and thus need little or no tweaking. Try it, if you haven't already, and you'll thank me.
YAY! I registered just to say thank you! :-)

With my old Celeron M Thinkpad I had major problems with HD videos since I updated VLC player some months ago - with other players like Media Player Classic etc. too!

Officially confirmed: Jetvideo (version 8.0.3.210) is awesome for HD videos if you have an old computer! I won't update THAT one! Haha! :lol:

Re: any VLC tricks for low power CPU?

Posted: 27 Apr 2017 03:55
by Hard Of Hearing
Just seen this thread...haven't tried any of the alternatives as yet, but, I do get the occasional video that gets jumpy.

Maybe someone can recommend an alternative player for me for these rare occasions.

My needs are :

1. A volume booster AT LEAST as powerful as the one VLC has. For most videos, my volume is at 200%.

2. A graphic EQ so I can tone down the bass to stop speakers/headphones distorting.

3. Mono playback as hearing fluctuates in each ear. This is ESSENTIAL to me - and also the reason I downgraded to 2.0.4 when it was removed from VLC.

*** PLEASE, before any nasty /sarky comments, notice my username ***

Re: any VLC tricks for low power CPU?

Posted: 27 Apr 2017 06:51
by VLCwin7User
3. If the audio output uses the DirectX module, if VLC is started with the --directx-audio-speaker=Mono parameter, I found stereo output was down-mixed to Mono

If you use the WaveOut module, the help says the parameter is --waveout-audio-channels=<integer [1 .. 9]>
So, vlc --waveout-audio-channels=1 outputs mono. I just tested that.
In preferences, there is an audio section with output modules. Mine was set to automatic and defaulted to the directX, since that parameter worked without changing the module.