The VideoLAN Forums

Hi,

I have VLC Player 1.1.11 installed on Windows 7 64-bit. I have a Dell Duo Core PC and 9500GT card installed. I am seeing a dpc latency issue only when playing video files w/ VLC player (playing in mpc-hc is fine). It is causing frequent popping audio noise.

If I use dpc latency tool I can see all the red bars (jumping up to 4000us) when playing the videos.


Most of these videos have AC-3 (2/6 channels) or AAC audios. The audio doesn't have to be 5.1 audio, and the CPU usage can be still low, but the DPC latency values are HIGH.

The funny part is this only happens with a new sound card I purchased : Xonar DG 5.1 PCI sound card. I was using a Creative Audigy 2 value sound card with no problem at all.


I seem to have located the culprit: if I turn OFF "Use hardware YUV->RGB conversions", then the DPC latency problem goes away.


All other VLC Player preferences are at the default values. That is, Video Overlay (hardware accelerated) is turned ON.

The help text says if Overlay is turned On then "Use hardware YUV->RGB conversions" should have NO effect -- true?


Just to be sure, I've tried demuxing the audio and playing just the demuxed audio is completely fine. But if I play the demuxed video part also at the same time with VLC player, it'd cause the audio popping noise immediately.


So to summarize :

Xonar DG + VLC Player "Use hardware YUV->RGB conversions" [ON] = high DPC latency => popping audio noise



Perhaps someone can look into this -- or if anyone might have a clue what's happening? Or it's purely the nVidia driver issue?

Thx... .

Forgot to mention :

playing the demuxed video only w/ YUV->RGB enabled, the dpc latency shows outbursts of 1000us (sometimes 2000us) latency every 2-5 seconds or so.

So definitely the video processing is already imposing some bursts of latency issues here. Adding the audio piece in and I woudl suddenly get 4000us latency right away.

For just the audio alone the latency is around only 500us or so, which is pretty normal... .

Yes. Some Video output modules are too aggressive about their timings, which can cause issues to audio output modules.