VLC2 - Lost Frames & Audio Resamplers

[FredFlange]

Hello All

This is going to be a bit long-winded, but I hope it will be relevant..

When I upgraded to VLC2 I had huge problems playing Video Files.

I mainly use .TS/.REC, but the problems I encountered were also evident in other formats such as .avi and .mkv.

PART 1. [Which I hope will be of use to others who encounter this problem]

The problem was that I was getting a large build up in Video Frames Lost, and this was causing the output to stutter slightly, and CPU usage to run at 90-100%. [I was experiencing no problems of this kind with VLC1.1.11 or Jet Audio].

I was most keen to get V2 working as it now provides a 'time count' and therefore bookmarking on .TS/.REC files. I tried everything, including updating and re-installing all my drivers, and changing just about every setting I could find but the only solution I discovered was to Disable Audio.[Not much of an option in the long term]

Eventually I came across a 'new' facility in the Audio Options called SRC resampler - The default option seems to have been set to the highest level [Sinc function (best quality)] - I adjusted this to the median setting [Sinc function (fast)] and this drastically reduced the CPU usage and eliminated the Frame Loss almost entirely.

PART 2 [Which I hope will further educate me in the workings of this great program]

I have done a little research [Googleing] and have a basic conception of resampling, but wonder if someone will just enlighten me a little further.

There are two resampler sections under the advanced Audio options : i. SRC resampler and ii. Speex resampler.

What is the function of each? Are they alternatives or are they called depending on the Codec in use? If the latter, when would the Speex be used, and would the settings for this have such a large effect as the settings for SRC?

Is the Default Install setting for SRC 'Sinc function (best quality)? If it is, is this wise given the problems it can cause?

If there is another forum where I am likely to get a better answer, please let me know.

Once again my grateful thanks to all who have made VLC 1 & 2 possible.

Regards

Fred F.

[kdean]

Regarding PART 1. That's already been fixed for 2.0.1 and now defaults to fast.

[Rémi Denis-Courmont]

Speex and SRC are different library providing different resampling algorithms. VLC 2.0.x prefers SRC if available.

Due to limitations in the audio output infrastructure, there is no way to select another plugin, other than deleting the SRC plugin and restarting VLC. In any case, If you have performance problems, I recommend you select the Zero-Hold algorithm in SRC, whose CPU cost is negligible. Linear is another cheap alternative.