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Best compression setting for Windows Media streaming over broadband and dialup?
I have a client who needs to stream a 5 minute 16×9 corporate candids video over broadband via Windows Media. The bit rate can be no more than 300 kbps with both video & audio combined. They also want a 100 kbps max file for dialup users. The full rez video exists as a self-contained Quicktime reference movie edited in DV and exported from Final Cut Pro.
We want to make the resulting .WMV file no smaller than 320×180. I have already tried a bunch of different settings and tests, but just can’t seem to get a decent looking resulting file at such a low bit rate. The version for dialup is so much worse… And I realize that trying to compress a candids video containing lot’s of handheld movement, graphics, small detail & movement within the frame, etc., and to make it look decent in Window Media is already a big challenge!
Any suggestions on what to do to make this video look its best at those specs?
Thanks!
-Mike
MAK Digital Media, Inc.
Orlando, FL -
6 Replies
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What application are you using to compress?
What other settings are you applying? (Deinterlace, keyframes etc)
Shaky DV footage is is going to be a challenge whatever.
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Using Apple’s Compressor and Flip4Mac. I am applying deinterlacing since it is originating from DV video for use on the web. My best settings were:
Video: 2-pass VBR at a bit rate of 236kbps, peak bit rate 472, 320×180, 29.97fps, Windows Media 9 Standard, Quality slider set to 0 for smoothest playback, Complexity control set at “Offline Slow”, Main profile, keyframe every 5 seconds, buffer delay set to 5 seconds, B-Frame distance at zero frames, input: interlace – lower field first, output: progressive.
Audio: 1-pass CBR at 64kbps, 44.1khz, stereo.
Client must have 300 kbps data rate or under.
MAK Digital Media, Inc.
Video Post-Production Services
Orlando, FL -
Can I suggest the following:
Keyframes every 10 seconds, (also try every 15 seconds)
Quality slider between 60% and 80%
Try a longer buffer delay.
Try B-Frames at 1 or 2
Have you applied any cropping?
Let us know how you get on.
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Please post back saying what solved your problem. It could help others, and saying ‘thanks’ is free! -
I would think that the distance between keyframes would have to be less, since there is so much action and quick cutting, but I will try what you suggest. I also found that particular to Flip4Mac, raising the Quality setting also ends up making both the data rate higher and the file size bigger. I’m not worried about size of the file though… it’s just keeping that data rate down that I have to stick with. And as for considering cropping, we’d really like to keep our playback in 16×9 aspect. Were you suggesting to crop the sides down to 4×3 or to make it letterboxed in 4×3?
This project was shot 4×3 in the past and I believe the final .WMV’s were delivered at 500 and 800 kbps at 320×240. My client even seems to think 300kbps was also delivered. They were the same candids style projects with graphics and the quality looks great. Unfortunately, the settings that were used on those projects are no longer available…
Thanks for the suggestions… I will try them and get back to you with the results…
-Mike
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The keyframes setting is basically saying ‘Force a keyframe every ‘x’ seconds’. Codecs will insert ‘natural’ keyframes when they see fit, at scene changes or when the difference between frames exceed a defined threshold. Forcing too many keyframes can have a bad effect on picture quality.
With the quality slider, if you choose a setting towards the ‘smoother’ end the encoder will drop picture quality in order to maintain a smooth frame rate, towards the ‘sharper end it will maintain picture quality at the expense of possibly dropping a frame or two. If you’re after high quality pictures then you’ll want to be in the range I suggested. At this kind of data rate you have to compromise.
The cropping I was suggesting was just a mild crop into the picture, to get closer to the ‘active’ picture not to change the aspect ratio.
Most cameramen still allow for an ‘action safe’ frame and the edges of the frame are sometimes ‘content redundant’ and as such can be discarded.__________________________________________________________________
Please post back saying what solved your problem. It could help others, and saying ‘thanks’ is free! -
So I did some tests with your suggested settings and they look promising.
Early on, I also tried to crop the image in equal amounts on all sides, but this appeared to somehow affect the video’s fields / field order. The input was interlaced, lower-field first, and output was intended to be progressive. Flip4Mac was supposed to deinterlace this video, but something was screwy there. I got rid of the cropping the file worked fine.
At one point, I started having problems with audio stuttering on playback. I checked the original Quicktime reference, which now was experiencing the same problem. After rebooting the computer though, audio playback on both the master Quicktime and the Windows Media encoded file were fine and back to normal.
I want to try some more experiments with your settings. Thank you for taking the time to write, and to explain some of these concepts. I’ll keep you posted here on my final results. Thanks!
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