Excessive "popping" noise when playing mp4 video with mp3 audio track

**tale** · November 17th, 2008, 10:36 AM

I've got all of my audio issues worked out now, except for this one issue which makes boxee almost useless for me. The vast majority of my movies I've encoded with mp3 audio tracks to save space.

I'm using Ubuntu 8.04. I've got xbmc install on this same machine and everything works fine with it. I don't have any audio issues at all. I have it configured to output digital audio out, with ac3 and dts pass through.

AC3 and DTS passthrough work properly. Music works properly. Streaming video from sites like hulu work properly. The only problem is a rhythmic popping noise as I play mp4 video with mp3 audio tracks. I can hear the mp3 audio in the background too. However the popping noise is quite loud, which prevents me from watching the movie.

I'm not getting errors in the log. Can anybody suggest a way to debug this issue?

**blackdog68** · December 26th, 2008, 10:28 AM

Too bad no replies on this. I was just doing a search to find an answer to the same question. I'm watching a movie encoded with AC3 6.1 sound. The sound is great, but there's a consistent popping throughout. I don't know if it's because my receiver can't handle it maybe. If I switch the audio to analog, the popping is gone, but of course so is the surround sound.

**blackdog68** · December 26th, 2008, 04:03 PM

I figured out the source of the problem, on my system at least. I had the volume on the television turned up as well as on the receiver. Once I turned off the television audio everything was fine. I assume it's because the TV can't handle AC3. (I am running hdmi from AppleTV to the television, and optical cable from the television to the receiver.)

**tale** · January 4th, 2009, 03:57 PM

This does not fix the issue for me. My system works fine when I use XBMC. The only thing I do is shutdown boxee and start XBMC. boxee has excessive popping and XBMC doesn't. I believe this is a bug in boxee. It only effects mp4 video with mp3 audio.

**tale** · January 6th, 2009, 09:31 PM

I finally fixed the issue. The change was quite simple. Under the audio settings, I set the output device to "iec958" and the passthrough device to "default".

Under XBMC, I have the output device set to default and the passthrough device set to iec958. I'm not sure why the opposite works in boxee, but I'm glad I've fixed my issue.