Re: High Quality Mpeg problem

An MPEG2 encoded video is compressed so you're never going to get a 100% equal copy to your original production. Every MPEG2 codec for DVD output does 2 things. First, it throws out about half your color data, reducing it to 4:2:0 YUV color space (your original is 4:2:2). Second, it compresses the video, which means it throws out some of the original data.

So even at the highest data rates, an MPEG2 video will be slightly less sharp, slightly less crisp than your original. There's no way around this fact...even using high-end hardware encoders.

Next problem...I believe the DVD spec limits the total video/audio data rate to something like 9800kb/sec. So you're exceeding the spec. Encore is telling you that, then re-encoding your video and audio to meet the spec. So you're basically compressing it twice. Once in Velocity making the MPEG2 file, and again in Encore. This seriously reduces the overall quality.

In your settings, you show that you have deinterlacing to "on." I believe it should be "off." Even if you shoot with a 30P or 24P, your video ends up being interlaced. It's way too complicated to go into in this thread...but I believe you're adding unnecessary processing and artifacts by deinterlacing your video on MPEG2 output.

You have video encoder quality at 50. I believe this should be set at the highest level available. If 50 is it, then you're ok...otherwise...take it up as high as it will go.

So, turn off de-interlace, increase your video encoder quality, and reduce your data rate in Velocity's output to an average no higher than about 7000- 7500 for the video portion. Sounds counterinutitive, but this should eliminate the re-encoding that's being done in Encore.

Also make sure you're outputting audio in a format that Encore expects. I believe it will take separate PCM .wav or MPEG layer 2 audio. If the audio isn't correct, I believe Encore will recompress the entire thing to meet that spec as well. I don't think you want to output a multiplexed MPEG2 file from Velocity (video/audio together in one file). Encore would probably de-multiplex it, possibly recompress, then multiplex upon creating your authored files. All unneeded steps in your process.

If that doesn't seriously improve quality, the only other solution is to output your Velocity timeline via hardware through SDI or component output to a dedicated hardware MPEG2 encoder.

Digital Rapids makes some very nice real-time encoding boards, but you're going to pay anywhere from $600 to $2000 for them. For my money, the quality increase is slight and only worth the cost if you're outputting a LOT of video to DVD's.

Hope that helps.

Chris Blair
Magnetic Image, Inc.
Evansville, IN.
www.videomi.com




Chris Blair
Magnetic Image, Inc.
Evansville, IN
www.videomi.com
Chris Blair
Magnetic Image, Inc.
401 E. Indiana
Evansville, IN 47711
www.videomi.com