The VideoLAN Forums

Using VLC 1.1.4 on an Acer Revo AR3610 (Intel Atom + nVidia ION) with Windows 7 x64 Home Premium (came installed by default) and latest drivers/firmware/updates/etc. I'm using the nVidia HDMI audio out and have it connected to an A/V receiver via HDMI, which passes the video on to my 1080p HDTV also via HDMI (the A/V receiver and TV parts work fine with other HDMI A/V devices such as a DVD player and a Tivo HD). The AR3610's video memory setting in the BIOS is set to the default 256MB, although I'm thinking of trying 512MB to see what that does.

I've noticed a few issues with VLC 1.1.4 on this setup:

1. Using the experimental accelerated video decoding is generally required for smooth playback of 1080p videos because the Atom CPU in the Revo is the weak point of the system, while the nVidia ION GPU is relatively powerful. However, when I enable this mode in VLC, the entire screen rapidly flickers black almost constantly when in windowed mode. If I run in fullscreen it usually works fine, however, so I've set VLC to start videos in fullscreen for now.

2. Videos with AC3 and DTS soundtracks get passed through perfectly to my A/V receiver when I have SPDIF passthru enabled in VLC (I can tell because VLC volume control is non-functional and my A/V receiver says "Dolby Digital" or "DTS"). However, non AC3/DTS videos (including videos with MP3 and WMA tracks) show as "PCM" on my A/V receiver, and my receiver refuses to perform Dolby ProLogic II decoding on them because it sees them as 5.1 PCM streams from Windows even though they are in stereo as far as I know (I tried setting both 5.1 and Stereo modes in the VLC DirectX output settings). I can force Windows to use stereo mode for the HDMI output instead of 5.1, which in turn reports stereo mode to the A/V receiver and triggers surround decoding, so I may do that (nothing to lose I guess since I don't really plan to play 5.1 Windows games on it)

3. Worst of all, however, is that in the non-AC3/DTS videos I get a subtle stutter every couple of seconds even though the video seems perfectly smooth.

Anyone have any ideas/comments/suggestions regarding these issues? Thanks!

1. is probably a driver bug. Try to change video output options to change this.
2. we need VLC messages for that
3. does it work correctly on the PC speakers?

1. I'll try that again and note down what I find. I should mention that I've also noticed that some videos have the opposite issue of flickering in fullscreen mode but not in windowed (?)

2. I've worked around this for now by reducing the nVidia HDMI output settings in Windows 7 to Stereo mode. This is an acceptable solution for me because I don't plan to output 5.1 sound from the HTPC other than via SPDIF passthrough. My A/V receiver now sees all non-passthrough audio as stereo and performs ProLogic II decoding on it as desired.

3. I've resolved this by changing VLC from DirectX SPDIF to Wave Out SPDIF. I've noticed slight pops/crackles/stutters in the audio of some video game console emulators, so I think the nVidia ION HDMI Audio driver must not play 100% well with DirectX audio.