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I'm looking to stream some video from Flash Media Live Encoder with a video bitrate of around 150 Kbit/sec and audio of 50 Kbit/sec. The video will contain quite a lot of movement which I want to try and represent as faithfully as possible. Is there a particular flavour of H.264 that I could use to optimise the results at a resolution of 384x216 i.e. which profile?

Thanks

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    I've never used that program but from the sounds of it, you've specified the codec, resolution and bit rate that you have/want to use, but aren't happy with the result? Don't think you can do much if you are set on those parameters... – Chard Jul 20 '11 at 5:33
  • This question seems more broadcast and compression specific than AV Production! There is a new site proposal Broadcast and Media Technologies which aims to capture more architectural and theoretical views around subjects like this. Join and invite others. – Dipan Mehta Mar 15 '12 at 19:58
  • What kind of videomaterial is it? – DoktorHauser May 14 '12 at 14:09
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If you are going for a lot of motion, make sure you set a higher I frame rate. An I frame is a whole frame that you are going to need with quick motion.

Also, check out this link http://www.adobe.com/devnet/flash/apps/flv_bitrate_calculator.html for some basic settings. That shows you that 150kb/s is way to slow to keep a good picture. For SD material, bitraters of around 500kb/s with fast motion is recommended.

  • This question seems more broadcast and compression specific than AV Production! Inviting experts to a new site proposal Broadcast and Media Technologies which aims to capture more architectural and theoretical views around subjects like this. Join and invite others. – Dipan Mehta Mar 15 '12 at 20:01
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It also depends a lot on your target platform. High Profile will compress better than Main Profile, but not all devices can decode High Profile with large frame sizes. A few cannot decode High Profile at all.

I have had considerable success encoding motor racing in SD (852x480, actually) at 768kbps using High Profile. Even though you have a quarter the frame size, I suspect 150kpbs is extremely optimistic.

  • This question seems more broadcast and compression specific than AV Production! Inviting experts to a new site proposal Broadcast and Media Technologies which aims to capture more architectural and theoretical views around subjects like this. Join and invite others. – Dipan Mehta Mar 15 '12 at 20:01
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It is generally impossible to say what settings will produce the best output for a given situation, without simply trying various settings. Most encoders (I have never used Flash Media Live Encoder specifically) have quite a number of settings that can be tweaked within a specific bitrate, frame rate, and frame size that will affect the final result. Some settings will have better results for some types of video than others.

My best advice, without knowing anything about your specific software, is to try various settings and compare the results. You may wish to encode the same 10-30 second clib (probably with a lot of movement in it, since that's one of your main concerns) with various settings, and compare the results.

Another thing I might suggest is lowering your audio bitrate so you have a little bit more video bandwidth. Although whether that's a good idea may also depend a lot on what your audio stream is like. If it's a music video, then you probably want to guard your audio bandwidth very jealously. If it's an interview (unlikely since you're talking about a lot of movement, but who knows?) then you can probably get away with pretty low audio bandwidth.

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