Choppy/stuttering ac-3 playback using HDMI!

[azmoth]

I recently bought a Philips DVP3580 upscaling player so I could utilize HDMI capability and its USB facility. The picture is excellent, but some of my avi's with Dolby 5.1 tracks will not play. The sound is very choppy and stuttery as if the sound/data cannot get through quick enough.

The avi's(Divx) meet all the requirements for video playback-I demuxed- and the video is not the thing causing this(I checked using MediaInfo as well), as I know Philips had a bit of a reputation as bringing out the first divx player with loads of compatibilty issues. In any case this is way more modern player since then. I changed my cheap HDMI lead to a more expensive one. Still the same. Tested it with my brother-in laws Sony cable. Exact same problem. All cables used are Category 2 cable rated and meet all to now modern standards. My TV is a Philips 1080p as well

Now thing is most of my avi's(Xvid/DivX with 5.1 tracks play okay. Yet if same problematic avi are played via USB, they play okay as standard stereo tracks. Also if I replace the HDMI with a scart no problems whatsoever. What could be causing this? I've heard of the HDMI handshake problem. I'm using a top quality 1m gold plated connector. Thanks.

It has me really perplexed!