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View Full Version : my videos start to stutter after awhile... why?


ellesshoo
16th November 2007, 16:06
I know my CPU can handle a 768x432 video, so I'm sure it's not on the playback side.

I think I have the wrong settings when encoding. I just did an encode (source was 1080i) to 768x432 and the video stutters like it's going forward then backward then forward again about 15 minutes into the 45 minute video. Here were the settings I used from my memory:

Main Profile: level 3.1
key frame interval: 250
B frames: 3
b slices: 2
use slices as reference
reference frames: 4
avg bitrate: 1280kbps
max bitrate: 8000kbps (my buffer size was set higher than the max so I don't think it is that).

Does the key frame interval have to be a multiple of the number of b frames? I'm trying again on a 20 minute portion of the same video but with the key frame interval set to 255 and b frames at 3. Are these just completely bad settings? This is for sports by the way. I just don't see how the video can play perfectly for almost 15 mins and then go bad. I can play other AVC videos of even higher CPU load and they don't do that so I think it's in my settings. I encoded successfully before but I've changed the settings so much I have no idea what I used to use. Thanks.

Dark Shikari
16th November 2007, 16:18
Those settings should be perfectly fine. What decoder are you using? Can you post a short clip of encoded video to see if the stuttering/etc is your problem or a problem with the stream itself?

ellesshoo
16th November 2007, 17:23
Those settings should be perfectly fine. What decoder are you using? Can you post a short clip of encoded video to see if the stuttering/etc is your problem or a problem with the stream itself?

I won't be able to until after the weekend. Thanks for the input though.