The VideoLAN Forums

I've got the impression that VLC for OSX has a huge problem with memory leakage, it seems to use all available RAM to map the whole movie clip while you are watching it. The explanation to this could be that it is a requirement for making it possible to start the clip where ever you want, without having to wait for a preload of the whole clip (like in Perian for example).

If the size of the movie clip is larger than your installed RAM (4Gb in my case), it starts stutter at the end of the clip when the OS needs to swap out the filled RAM to HDD.

You would think that closing VLC and "kill" it would free upp all memory mapped/reserved by VLC, but it doesn't. You need to either put the movie clip in the trashcan and empty it or reboot your mac, to get your lost RAM back.

I'm gonna try disabling MMap and see if that does the trick.

Edit: Well, disabling MMap didn't do the trick. After one movie clip (4Gb .mkv) all my RAM is occupied and before I emptied the trashcan with the movie clip I wouldn't get any RAM back.

I've got the impression that VLC for OSX has a huge problem with memory leakage, it seems to use all available RAM to map the whole movie clip while you are watching it. The explanation to this could be that it is a requirement for making it possible to start the clip where ever you want, without having to wait for a preload of the whole clip (like in Perian for example).

I have never had the same problem. I routinely watch 3-8GB mkv files and VLC is rarely using much more than 100MB of RAM. I leave it open for days at a time as I am always pausing and going back to videos that are left open. I would also know the difference if it were somehow trying to buffer the whole file first. My network is gigabit and I am almost always watching from a server, but everything starts instantly.

Thanks for your reply, bradmurray!
Have you disabled MMap as well?

I'll have to take back what I stated in my previous post.
After a couple of days (after restart/reboot?) VLC doesn't longer seem to use up all RAM, it's almost like the disabling of MMap didn't have any effect at first (when I edited my post).
Anyhow, now VLC seems to work as it should and I'm happy as I ever could be. No more rebooting or throwing movies away to get my lost RAM back.

You might have noticed a performance decrease within the last few releases or finally when updating to Mac OS X 10.6 Snow Leopard.

If you did, try this:

* Go to VLC's preferences
* Click on "All" at the bottom of the window
* Navigate to "Input/Codecs" -> "Access modules" -> "MMap"
* Activate "Use file memory mapping"
* Save the settings and restart VLC.

Afterwards, VLC should perform as expected. We will enable this setting by default in future releases of VLC for Mac OS X.

Hey everyone,

I am running 10.6 and when I attempted to follow these directions, I noticed "Use file memory mapping" was already activated/selected. So at this point, I did the opposite and unactivated/unchecked "Use file memory mapping". Every since then, I have not had any problem playing back .MKV file from standard DVD or Blu-ray DVD.

* Activate "Use file memory mapping"
* Save the settings and restart VLC.

Afterwards, VLC should perform as expected. We will enable this setting by default in future releases of VLC for Mac OS X.

Until the free memory is gone maybe, then what...
After having played a DVD or what ever, all free memory is gone and everything is sluggish, frozen and unresponsive. It probably worsens the situation for HD-video as well after a short time when the free memory is used up (?). I think Activate "Use file memory mapping" should come with a warning!

Here the "Use file memory mapping" is now turned off and will stay turned off. Now I can actually use my computer as normal after having watched a movie.

When comparing if using "file memory mapping" helps, I suggest not playing a part of a video that has already been played with file memory memory turned on, because (I am guessing) it will play what is cached from memory instead of the harddrive. Always try it on a new part or use iFreememory (or such) to clear the caches in between. A short video will probably play better the second time with "file memory mapping", so it may be deceiving...

Remeber the disadvantage of using "file memory mapping" in my previous post. Maybe it is good sometimes, but certainly not always...

2010 Mac Pro 5.1, OS X 10.6.5, ATI 5870, 10GB RAM

VLC 1.1.3 and 1.1.5 both experienced video/audio stuttering when playing avi files. I unchecked "Use file memory mapping", which was on by default, and the stuttering disappeared in both versions. What's really strange is that the problem only occurred with files stored on my WD 2TB Caviar Black hard drives. Identical files on both of them produced the same glitches. I had no problems with memory mapping playing videos from my 1 TB Caviar Black, or my SSD. Thankfully, all is well now that memory mapping is disabled.

MacBook Pro 1st gen
10.6
2 gig ram <~ that's all it can take
VLC 1.1.5
Settings Map feature like above comments On and Off

Video: MKV 1080p file size around 800megs
I still get 'some' VLC quality artifacts but far less than previous versions.
MKV's take awhile to load now but all players do that. Quicktime's, MPlayer

I found out about the purge command in terminal as well to free up some memory now and then.
If I turn Map feature off skipping through the video will delay the audio. With map turned on it's fine.

This brings up another question. Why do MKV's have this long load system? I assume they are getting copied into memory to play. But the video file in them is just h.264's and a normal .mov file or mpeg file never has to load like this.

I thought VLC would read them differently. Saa~

In addition it also helps to disable the fullscreen menu if you only have stutters in fullscreen.

Thank you! I registered just to inquire about this, but thankfully I ran into your thread.

We will enable this setting by default in future releases of VLC for Mac OS X.

You promised that in 2009, and it's still not enabled by default. If that's not the proof that Mac users are third-class citizens, I don't know what is.

Regarding playback of 1080p .mkv videos: I was having trouble when viewing long zooming shots or pans - motion was jerky, not seamlessly smooth. The main cause turned out to be that I had checked the "sharpen video filter" a long time ago when watching low definition material, and had forgotten about it. It uses a chunk of processing power and is not necessary with HD material.

This fixed that issue, but there were still problems like when a flock of hundreds of thousands of birds took to the sky all at once. Data overload! and the picture would freeze till the action was over. This was fixed by going to Preferences (All) / Video Codecs / FFmpeg there on the 13th line down I changed the "skip the loop filter for H264 decoding" from None to All. I'm happy with the result.

So not as easy as many people would expect from VLC. However, main thing is that it works (somehow)!

thanks for your update...it works again

I have just bought a MacBook Air 13" Mid 2011 with 1.8Gz and i7 4Gb Ram 265 SSD

Had choppy HD video 1920x1080 playing thru VLC. The file was .mts-

The fix was VLC->Preferences->input & Codecs->Post-Processing Quality 0 (set it to ZERO)

Have Fun! No more choppy videos

For a very long time I have not encountered the stuttering using various files (mkv and mts mainly in the past year). Not since maybe 5 years ago. Even in the past month I've been using it frequently with mts files of live concert recordings, no problems.

Until tonight. I transferred a new set of mts files of a concert I recorded, and upon playback every file had a stutter merely 15 seconds into playback. I immediately thought it was just a problem with the files, so I went and played mts files of concert footage I recorded/transferred in December (which had no stutters, smooth playback at various sizes etc.) and found that these too began to stutter at the same points.

I have tried all the solutions offered here and elsewhere with none being useful at all. I would like to know why suddenly all my mkv/mts files are stuttering during playback in VLC player now? Possible solutions, is anyone else encountering this? I haven't changed anything I've done in using the application or transferring files (in terms of size, quality, etc.) so I'm baffled as to why it started happening just now.

Reset preferences in VLC.

I am on a MacBook Pro 17 OS X 10.7.3 with 2.66 GHz Dual Core with 8GB RAM and 500GB HDD.

I have had very juddery playback with most video files (mkv and avi) of all sizes - it looks like an old hand cranked silent film. It occurs in all cases - on a second screen (an HD projector) and on my MacBook's screen - in both cases in window and fullscreen modes. I don't have the problem with QT Player or QT Player 7 - but there are other reasons why they are not suitable - especially on Lion.

I tried every tip in this thread without success. I just downloaded v2.0.0 hoping that something might have changed to fix the problem but it's still there. Additionally, now the preferences layout has changed and I can't find half of the preferences sections to try the fixes again.

I'm sure this wasn't a problem for me until about a year ago.

Any fresh thoughts about this?

I have just downloaded VLC2.0.0. Previously VLC worked wonderfully for, inter alia, AVCHD and .ra files. Now it plays .ra files in 1-second bursts, and all my AVCHD footage is now unplayable - jerky, distorted and grossly pixellated. This applies to the codecs from different camera manufacturers. Anyone else have a similar problem?

MacPro, 12-core, 2.93GHz, 17GB Ram, Lion 10.7.3, ATI Radeon HD5770 1024MB

please share logs and Samples.

I have grabs of two adjacent frames from a boat-building video which played just fine under the previous VLC version - Panasonic camera this time - shewing a so-so image and a completely unviewable image. How do I share them?

Any way is ok.

The only way I know of is email.

imgur.com

http://imgur.com/u3sRS
http://imgur.com/FPAre