The VideoLAN Forums

I have several 1080p .mkv files. All are avc1 encoded. All three have unique issues when playing in The Core Media player/Media Player Classic with the coreavc codec. With VLC they all open, and audio is crystal clear, but the video is very choppy. Using TCMP and MPC, the video plays fine for a few, but some that are dts encoded have choppy audio, whereas they don't in VLC. One wont play at all in TCMP/MPC, but opens fine in VLC, but like the others, only the audio works. I'll have maybe 10 seconds of perfect video, then it will simply display 1 frame for another 10 seconds. It corrects itself, plays for a short while, then pauses again on a random frame. I've tried all the different video output modes, Windows GDI, which looks like crap, plays all the movies fine. Any other display mode and it does the random frame-freezing. So, is there anyway to force VLC to use a different codec, or are there recommended tweaks for vlc to increase avc1 performance?

I should mention, I have several 720p movies encoded with avc1, all play fine in VLC. Why should I require the coreavc codec and a different media player just to play a slightly higher def movie?

1080p is actually a lot higher hefinition than 720p as it is to the square of the vertical pixel increase (as an area). Assuming full size 720p, the resolution is:
1280 x 720 = 921600 pixels

And for 1080p:
1920 x 1080 = 2073600 pixels

So, dividing the 1080p size by the 720p size: 2073600/921600 = 2.25 times the size.

Which means (in theory) 2.25 times more processing power is required to decode a 1080p video than a 720p video.

As I said in another thread:

Yeh - AVC1 is quite CPU-hungry in comparison to, for exmaple, XviD. See here:
viewtopic.php?f=12&t=33698&p=104317&hil ... PU#p104317

So, transcoding to a different Video codec (and/or scaling the video down) should reduce the high level of CPU usage.

Arite.

Unfortunatley I do not know of any tweaks for VLC to improve performance decoding AVC1.

Cheers, Arite.

I always suggest updating graphics card drivers and DirectX drivers and use the “DirectX video output” module, once all of that is done then try changing the loop filter to all (Preferences -> (tab) Input / Codecs -> (tab) Other codecs -> FFmpeg -> select the drop-list next to “Skip the loop filter for H.264 decoding” and set it to all, save and restart VLC.

Thanks - I will have to try that out next time I play an HD AVC1 file.

Arite.

Thanks for the suggestion. I have the latest Ati drivers, the card is an x1950pro, so it should be enough. The fact that I can play 1080p with a specific codec, suggests to me that under those conditions, my hardware has the processing power to play such a high resolution video. I will try those settings in VLC when I get home tonight.

well, switching to directx video, like I've done before didn't make a difference, and neither did the loop trick. Any other ideas?

I should mention, I have several 720p movies encoded with avc1, all play fine in VLC. Why should I require the coreavc codec and a different media player just to play a slightly higher def movie?

well, your statement requires 2 distinct clarifications :

1. video playback uses just about every susbsystem, not just the video player software : CPU, GPU, hard disk real sustained throughput, et al
2. 1080 video currently pushed current hardware to the limit (even Dual Cores).

I suspect your PC - not VLC - is the problem. You should check if your GPU provides some sort of H264 acceleration, through what software, and use that.

cheers
enkidu

Please take a look at this thread:

https://forum.videolan.org/viewtopic.php?f=14&t=41274

Enable GPU acceleration in Input and codec settings and change lower video quality post-processing level to 0. Sure, you will get good results by this.

genothomas: please, don't wake up threads this old.

I'm glad "genothomas" resurrected this old thread. I found it in the top result of a Google search when I was having trouble playing back a 1080p mp4. I followed genothomas' advice and my video is playing back perfectly as I type this. No more stuttering, no more freezing, no more garbled pixels. Resurrecting old threads isn't so bad, is it?

Check the driver on your video card. My playback was choppy, too. I went into device manager, and found I had an uninstalled VGA driver. I installed one that's compatible with the video on my board, and viola, the 1080p plays perfectly. I run WinXP SP3. If your VGA driver is installed correctly and the movie still won't play right, then it's some other issue. Can't say what without being there.

I am also glad GENOTHOMAS resurrected this old thread...

as it also saved my ass.. I been having choppy video playbacks and was wondering what da heck was wrong... it plays fine in windows media player classic but not VLC!!!

the setting mention by genothomas worked well!!!

THANK YOU SO MUCH for your help... I been searching for this fix for a while

PS... I am resurrecting this old thread in hopes it will save someone who is having similar issues with choppy video play backs.. studdering.. and garbled pixels.

In respect to GENOTHOMAS', how do you do so In the newer updates for VLC? I can't seem to find out how. Help would be greatly appreciated!

In VLC, go to:
Tools >> Preferences

And in the "Inputs / Codecs" section change the "Hardware-accelerated decoding" setting. "Automatic" is probably best. Click "Save", restart VLC for good measure, and try a video.

Arite.