FFmpeg multithreaded encoding with SCR about screen-capture-recorder-to-video-windows-free HOT 17 OPEN

what command lines did you use? if you're encoding to libx264 it should
by default use multiple cores, AFAIK

On Thu, Nov 6, 2014 at 1:31 AM, Andras Fuchs [email protected]
wrote:

I've tested some cases and it looks like ffmpeg can't use the
multi-threaded encoding with screen-capture-recorder. It might be a problem
with ffmpeg's way to handle dshow inputs, I don't know.

Did anyone else had the same experience? It tried to record a full-hd
screen and could not get above the 25% CPU usage on my 4-core machine. I
tried both 32 and 64 bit Zeranoe builds (http://ffmpeg.zeranoe.com/builds/
).

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#49
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Yes, I also think it should, that's why I'm surprised. I tried to do the encoding with both x264 and x264rgb with the same results.
The multi-core functionality worked fine when I selected a video file as an input though.

Here are my command lines:
1,
ffmpeg -loglevel warning -f dshow -i video="screen-capture-recorder" -f dshow -i audio="Microphone (Samson Meteor Mic)" -vcodec libx264 -preset ultrafast -pix_fmt yuv420p -s 1280x720 -vsync vfr -acodec libmp3lame -f mpegts - | ffmpeg -f mpegts -i - -c copy "test_x264_01.mp4"

max. 25% CPU

2,
ffmpeg -loglevel warning -f dshow -i video="screen-capture-recorder" -f dshow -i audio="Microphone (Samson Meteor Mic)" -vcodec libx264rgb -preset ultrafast -crf 0 -pix_fmt rgb24 -s 1920x1080 -vsync vfr -acodec libmp3lame -ac 1 -ar 44100 -b:a 96k -f mpegts - | ffmpeg -f mpegts -i - -c copy "x264rgb_crf00_uf_rgb24.mp4"

Max 25% CPU

and

3,
ffmpeg -loglevel warning -i x264rgb_crf00_uf_rgb24.mp4 -vcodec libx264 -preset ultrafast -pix_fmt yuv420p -s 1280x720 -vsync vfr -acodec libmp3lame -f mpegts - | ffmpeg -f mpegts -i - -c copy "test_x264_01.mp4"

Max. 45% CPU

I used the latest (2014-11-05) Zeranoe 64 bit build for the tests...

from screen-capture-recorder-to-video-windows-free.

my guess is that it's using multi-thread but that your system has enough
CPU to keep up in realtime [?]

On Thu, Nov 6, 2014 at 6:34 AM, Andras Fuchs [email protected]
wrote:

Yes, I also think it should, that's why I'm surprised. I tried to do the
encoding with both x264 and x264rgb with the same results.
The multi-core functionality worked fine when I selected a video file as
an input though.

Here are my command lines:
1,
ffmpeg -loglevel warning -f dshow -i video="screen-capture-recorder" -f
dshow -i audio="Microphone (Samson Meteor Mic)" -vcodec libx264 -preset
ultrafast -pix_fmt yuv420p -s 1280x720 -vsync vfr -acodec libmp3lame -f
mpegts - | ffmpeg -f mpegts -i - -c copy "test_x264_01.mp4"

max. 25% CPU

2,
ffmpeg -loglevel warning -f dshow -i video="screen-capture-recorder" -f
dshow -i audio="Microphone (Samson Meteor Mic)" -vcodec libx264rgb -preset
ultrafast -crf 0 -pix_fmt rgb24 -s 1920x1080 -vsync vfr -acodec libmp3lame
-ac 1 -ar 44100 -b:a 96k -f mpegts - | ffmpeg -f mpegts -i - -c copy
"x264rgb_crf00_uf_rgb24.mp4"

Max 25% CPU

and

3,
ffmpeg -loglevel warning -i x264rgb_crf00_uf_rgb24.mp4 -vcodec libx264
-preset ultrafast -pix_fmt yuv420p -s 1280x720 -vsync vfr -acodec
libmp3lame -f mpegts - | ffmpeg -f mpegts -i - -c copy "test_x264_01.mp4"

Max. 45% CPU

I used the latest (2014-11-05) Zeranoe 64 bit build for the tests...

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#49 (comment)
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from screen-capture-recorder-to-video-windows-free.

-preset ultrafast
chnage to
-preset slow

now you should have 100% :D

from screen-capture-recorder-to-video-windows-free.

Oh, bloody hell, you're right, it's 70% now :D

But then, how come that I can't capture more than 15 fps in 1920x1080?
(I've set the max fps in SCR to 100)

from screen-capture-recorder-to-video-windows-free.

you must set more for real time buffer. Like 400M

from screen-capture-recorder-to-video-windows-free.

ffmpeg -loglevel info -re -rtbufsize 400M -f dshow -i video="UScreenCapture" -f dshow -i audio=
...

from screen-capture-recorder-to-video-windows-free.

and dont use ultrafast never. Practicial use is veryfast preset for live capture

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@mca64
Thanks for the tips!

The default parameters were the following:
ffmpeg -loglevel warning -re -rtbufsize 10M -f dshow -i video="screen-capture-recorder" -f dshow -i audio="Microphone (Samson Meteor Mic)" -vcodec libx264rgb -preset veryfast -crf 1 -pix_fmt rgb24 -s 1920x1080 -vsync vfr -acodec libmp3lame -ac 1 -ar 44100 -b:a 96k -f mpegts - | ffmpeg -f mpegts -i - -c copy "test_x264rgb_scr_re_rtbs010M.mp4"

I've made some tests:

• without RE, without rtbuffersize | 13.063 fps
• without RE, with 10M rtbs | 13.104 fps
• with RE, with 10M rtbs | 11.732 fps
• without RE, with 800M rtbs | 12.877 fps
• with RE, with 800M rtbs | 11.713 fps

@rdp
Is it possible the SCR can't feed the data fast enough for FFmpeg?

from screen-capture-recorder-to-video-windows-free.

did you disabled Windows Aero on Windows 7? On Windows 8 you cant do that without little hack. What OS do you have?

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btw this is painful libmp3lame -ac 1 -ar 44100 -b:a 96k
use something like this
libmp3lame -q:a 2 -ar 44100
or -q:a 0 (MP3 V0) or even CBR 320. MP3 V2 is close to audio transparent. Preserve quality! ;)

from screen-capture-recorder-to-video-windows-free.

Probably not, I have Win 8.1. I'll try again after disabling Aero.

You're right, the above settings are for testing only.
SCR uses 44kHz, 2 chan, CBR 128 by default, I think.

from screen-capture-recorder-to-video-windows-free.

so you cant use it for higher framerate on Windows 8. Unless you will sespend there winlogon.exe process, kill explorer.exe and dwm.exe

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RDP please add support for fast Windows 8 desktop capture
here you can see how they did it in OBS https://github.com/jp9000/OBS/blob/master/Source/DesktopImageSource.cpp

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@mca64 Wow, this OBS is awesome! 👍

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someday I might even own windows 8 LOL

On Thu, Nov 6, 2014 at 9:56 AM, mca64 [email protected] wrote:

did you disabled Windows Aero on Windows 7? On Windows you cant do that
without little hack. What OS do you have?

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#49 (comment)
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from screen-capture-recorder-to-video-windows-free.

@rdp Nah, Windows 7 FTW.

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