ffmpeg and avc1 compression

[romanov88]

Sorry! my english is bad!
How to compress avc1 video with minimal cost?I have OBS + quick sync -> 2nd computer -> rtmp server -> ffmpeg -> twitch
So, I need to compress from 10 000k video to 3 000 k at minimal cost...
After OBS:
Video #2
ID : 2
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L3.2
Format settings, CABAC : Yes
Format settings, ReFrames : 2 frames
Muxing mode : Container profile=High@3.1
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 6s 250ms
Source duration : 6s 225ms
Bit rate mode : Constant
Bit rate : 9 200 Kbps
Nominal bit rate : 10 000 Kbps
Width : 1 280 pixels
Height : 720 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 60.000 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.250


I need to compress it to 3000kbps. What should i do?


Re-stream whithout compression ->20% cpu


ffmpeg -re -i "rtmp://xxxx" -f flv rtmp://twitch

only with -c copy it works without cpu utilization


ffmpeg -re -i "rtmp://xxxx live=1" -c:a copy -c:v copy -f flv rtmp://twitch

I'm using this to compress, but maybe it's not best solution.....
ffmpeg -re -i "rtmp://xxxx live=1" -c:a copy -crf 25 -preset veryfast -vcodec libx264 -b:v 3000k -maxrate 3000k -bufsize 3000k -f flv rtmp://xxxx

Please, ANY help is welcome. Thank you!

[Selur]

"at minimal cost..." = minimal encoding time, then enable:
a. preset ultrafast
b. tune zerolatency

[romanov88]

"at minimal cost..." = minimal encoding time, then enable:
a. preset ultrafast
b. tune zerolatency

i know that i can choose another preset..... but mb i should use another codec or programm (ffmpeg doesn't support openCL)

[Selur]

Problem there is that I don't know of any encoder/tool which offers:
a. support for input via pipe (or can capture rtmp streams)
b. support for QuickSync/CUDA/OpenCL (de- and) encoding
c. can passthrough audio
d. can output to flv
so not all hope is lost, but I wouldn't hold my breath.

-> aside from writing your own application based on ffmpegs rtmp input code, some QuickSync-/CUDA-/OpenCL-SDK and ffmpegs flv muxing code; the normal ffmpeg seems to be your best choice.

[romanov88]

Problem there is that I don't know of any encoder/tool which offers:
a. support for input via pipe (or can capture rtmp streams)
b. support for QuickSync/CUDA/OpenCL (de- and) encoding
c. can passthrough audio
d. can output to flv
so not all hope is lost, but I wouldn't hold my breath.

-> aside from writing your own application based on ffmpegs rtmp input code, some QuickSync-/CUDA-/OpenCL-SDK and ffmpegs flv muxing code; the normal ffmpeg seems to be your best choice.

Can wowza do it?

[Selur]

No, clue never used Wowza Media Server, best ask their support.

[romanov88]

Thx for your help! And one more qustion. How can i convert rtmp to directshow and then import in OBS ( OBS support openCL)?

[Selur]

iirc there are some rtmp DirectShowFilter out there which allow you to grap rtmp stream through directshow, but no clue how to use OBS with that.

[romanov88]

will ffmpeg works faster (re-encode h264->x264) on 2xXeon E5-4617 (12core 24th) than on 6 core 3930k@4.5GHz? (How it`s scales from extra threads?)

[Selur]

Don't know. http://www.techarp.com/showarticle.aspx?artno=669 might help a bit, normally x264 itself scales nearly linear (in core count and clock rate), but the input speed might still be limited by the hdd, the decoder,....