[mythtv-users] Minimizing bandwidth with MPEG-4

Andy Kuan andy at kuan.net
Wed Mar 31 10:52:38 EST 2004

I've been trying to come up with encoder settings for MPEG-4 that 
provide the lowest possible bandwidth utilization. This is in the hopes 
of being able to watch (grainy) TV on my desktop at work. It _almost_ 
runs smoothly for me right now.

My current settings are 160x160 MPEG-4 at 100kbps, max qual 2, min qual 
15, qual diff 3, 4MV and hi-qual checked, MP3 sampled at 32000 at a 
quality of 9. These settings will produce a 50M file for a 30 minute 
show. That's around 200kbps which is 2/3 of the upstream capacity on my 
cable modem (which makes me wonder why it isn't 100kbps as set -- ah 
well). I tried watching some baseball from the office yesterday and 
experienced momentary drop outs (~1-2 sec) every 10 seconds or so -- so 
I know I'm close. I figure I'll never get the full 300kbps upstream from 
my cable modem, so my target should be around 150kbps for my encoding 

I don't believe the 4MV and hi-qual MPEG-4 settings will make a 
difference. That leaves changes to the max qual, min qual, and qual diff 
settings for MPEG-4 and the audio settings. Unfortunately I haven't seen 
any documentation whatsoever on how to adjust those MPEG-4 quality 
settings (except for warnings _not_ to touch the settings) and there 
isn't a control to alter the bitrate of the MP3 audio.

Has anyone else attempted this or have any suggestions? Thanks!

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