Sorenson codec

ctbarker32 wrote on 4/9/2002, 4:38 PM

Hi,

I've been experimenting with compressed video renders from VV3. The best quality for the least space so far seems to go to the Sorenson codec. I've settled upon a 75 to 85k bit rate. One thing that is curious is I get better results with Sorenson V2 compared to Sorenson V3. The Sorenson V3 mov file suffers from alot of blur at the same bit rate as my V2 sample. I'm using the built in codecs that come with VV3. Usually the newer version of a codec is better. In my tests this is not the case.

In my tests with Windows media so far, I have been unable to get as good quality as the Sorenson at the equivalent bit rate and file size. I find the default templates for all these codecs less than optimal. I've had to play with settings alot.

Anyone have suggestions for optimal compresson strategies. Right now I'm going witha 24x180 window size.

Thanks.

-CB

Comments

Cheesehole wrote on 4/9/2002, 5:34 PM

>>>Anyone have suggestions for optimal compresson strategies. Right now I'm going witha 24x180 [240x180] window size.

my suggestion: either increase the bitrate, or decrease the window size. you'll get much better results. if you are looking to improve quality, that's where to start.

also consider filtering the content with Quick Blur or Median Filter (slow!).

ctbarker32 wrote on 4/9/2002, 11:07 PM

I mistyped I am using 240x180 which is pretty small. I am playing with bitrates as well.

-Cb

Stiffler wrote on 4/10/2002, 2:52 AM

Ctbarker32...

So...for a newbie, how do you increase the bit rate? And where do I find that codec?

Thanks, Jon

Cheesehole wrote on 4/10/2002, 9:12 AM

I've had better luck with the command line version of the Windows Media 8 encoder than the built in Vegas encoder. (download it from Microsoft) I use two-pass CBR as an encoding mode and get great results especially at 30fps. I can send you my encoder presets if you want. you have to render to an uncompressed AVI from Vegas and then feed it through the encoder. DV files work great too if you want to conserve disk space. it's easy to use once you set up some presets, but you do have to know how to use the command line.

- cheesehole!

ctbarker32 wrote on 4/10/2002, 6:31 PM

cheesehole,

Yes, please send me your presets if it would not be too much trouble.

Out of curiosity, when you render to a file directly from VV3, does VV3 render to a intermediary format such as avi? Not clear why I would need to render to avi then perform the wma endcode. BTW, I installed the MS Media producer which installs the WMV 8 encoders which I am using from within VV3. I was having some issues with WMA sound quality from Acid a while back when I installed the new MS encoder with the updated WMA 8 encoders I got better results. I did both with the command line version and then from within Acid/Vegas and now get identical results.

email: cbarkerpublic@comcast.net

Thanks.

-CB

Cheesehole wrote on 4/11/2002, 7:02 AM

sorry I just realized all my presets are for high bitrate stuff. I'm not sure a 1 Mbps or 4 Mbps preset will be helpful to you, but here they are (see below). just save the text into a .weu file (hi_q_1024.weu for example) and you can use them with the command line encoder.

I mentioned rendering to an intermediary file because you have to do that to use the wm8 command line encoder utility. thanks for the info about solving your Acid problem. I'll have to double check my results from Vegas to see if anything has changed since I've installed the wm8 encoding utility.

the problem I saw, is the files rendered from Vegas to wm8 did not play smoothly and had a lot of audio break up. looking at the statistics while viewing the file revealed a lot of "breaks" in the audio. I compressed the same footage using the command line wm8 encoder, and got perfectly smooth files with perfect audio. I've never gotten a file that breaks up on playback from the wm8 encoding utility, so I'm sticking with that. it fully utilizes dual processors just like the Vegas version so it's nice and fast!

here are my high bitrate presets. the frame rate is determined by the source file. when possible, I use an uncompressed AVI at 30fps as a source.
medium quality 2-pass CBR 1024K preset:
-a_setting 128_44_2
-v_bitrate 1024000
-v_quality 75
-v_buffer 3000
-v_keydist 3
-v_mode 1

high quality 2-pass CBR 4096K preset:
-a_setting 128_44_2
-v_bitrate 4096000
-v_quality 95
-v_buffer 3000
-v_keydist 3
-v_mode 1

ctbarker32 wrote on 4/11/2002, 9:27 AM

cheesehole,

Interesting comment on the audio breakup problem. I have noticed this as well! I wasn't sure what was causing this.

It would be nice if someone from SF could comment on why it seems you can get better results using command line tools for WMV 8 than using the VV3 GUI. I'll have to run my own tests with the command line tools for video now that you've raised these points.

-CB