Purple line occasionally at the bottom of mpc-hc when playing vc1 mkv

I'm having trouble with my rip of Supernatural Season 4 on blu ray. I ripped Supernatural into individual mkvs, with vc1 video and ac3 audio inside of each; and subtitles in IDX. I used AnyDVD HD and Another Eac3to Gui to do the ripping.

In episode 6, Yellow Fever, there is a purple line at the bottom of mpc-hc during certain scenes. In the episode, Sam is fighting with a ghost, and it seams like multiple cameras were used to film the scene. The purple line will appear, and continue to be there, until the scene shifts to a different camera angle. Then the purple line will be gone. Then the camera angle shifts again, and the purple line is back. During the episode, the purple line is only present during this fight scene. I remember the purple line appearing in 1 or 2 other episodes, before episode 6. But it doesn't appear in every episode. And it only seams to effect mkvs with vc1 video.

I haven't encountered this problem with mkvs with h264 video. I have the movie Watchmen as an vc1 mkv, but I didn't encounter the purple line in that movie. I have tested the episode in VLC player, and the purple line is also present there.

I have my system setup using GreenEyez' HTPC Software GUIDE for Windows 7 Media Center. I used the "MKV Playback using MPC-HC as an external player" part of the guide. I don't have hali media splitter installed; but otherwise I followed GreenEyez' guide. As per his guide, I'm using FFdshow as my preferred audio decoder in mpc-hc.

Any help figuring out how to get rid of the purple line, would be greatly appreciated.

I should also point out that my pc has a i7 930 cpu, an ATI 5870 graphics card, 6 GB of DDR3 memory, and an Asus P6X58D-E motherboard. I have an hdmi cable running from my graphics card to my receiver, a Denon AVR 3808ci. From the receiver, I have an hdmi cable running to my TV, a Samsung LN-T4071 LCD.

Thanks for your help dbone. I was starting to give up hope.

I agree, Supernatural does rock. It's such an outstanding show that it's always seemed out of place compared to the rest of the CW's poorly made shows.

My mpc-hc build number is 1.3.2099.0

Under Internal Filters, Transform Filters, I have VC-1(DXVA) and VC-1(FFmpeg) both checked off. Are you saying that I should unckeck VC-1(FFmpeg)? I'm noticing that I have everything checked under the Transform Filters column. But under the Source Filters column, I have everything checked, except Matroska. I'm wondering if that could be the source of my problem. Should I put a check mark next to Matroska? (Edit) Never mind, I just tried everything in the above paragraph, and the purple line remains.

I just tried the Microsoft DTV-DVD Video Decoder by going to the External Filters tab, and then added it as a filter. I set it as preferred and set ffdshow audio decoder to "block." The purple line is still there.

Here are the time stamps for when the purple line appears during episode 6, Yellow Fever, of Season 4: 34:41 to 35:00, 35:09 to 35:15, 35:19 to 35:20, etc.

Bump.