[FFmpeg-user] How to scale FFmpeg

imalkevich at gmail.com imalkevich at gmail.com
Fri Mar 12 10:50:51 EET 2021


Hi,

Here are the three commands used:
ffmpeg -threads 0 -loglevel repeat+level+verbose -f lavfi -i testsrc2=s=1920x1080:r=30 -f lavfi -i sine -c:a aac -ar 48000 -b:a 64k -c:v libx264 -crf 18 -preset medium -tune zerolatency -pix_fmt yuv420p -f mpegts - > NUL1
ffmpeg -threads 0 -loglevel repeat+level+verbose -f lavfi -i testsrc2=s=1920x1080:r=30 -f lavfi -i sine -c:a aac -ar 48000 -b:a 64k -c:v libx264 -crf 18 -preset medium -tune zerolatency -pix_fmt yuv420p -f mpegts - > NUL2
ffmpeg -threads 0 -loglevel repeat+level+verbose -f lavfi -i testsrc2=s=1920x1080:r=30 -f lavfi -i sine -c:a aac -ar 48000 -b:a 64k -c:v libx264 -crf 18 -preset medium -tune zerolatency -pix_fmt yuv420p -f mpegts - > NUL3

All the presets are 'medium' now.

And here are the outputs:
[info] frame= 2222 fps= 25 q=17.0 size=  124402kB time=00:01:14.03 bitrate=13765.4kbits/s speed=0.835x
[info] frame= 3441 fps= 19 q=18.0 size=  192778kB time=00:01:54.68 bitrate=13769.8kbits/s speed=0.631x
[info] frame= 2632 fps= 17 q=18.0 size=  147456kB time=00:01:27.70 bitrate=13773.6kbits/s speed=0.582x

Thanks for the note about tee muxer, I read that it can send output to multiple locations, but in my particular example I'm trying leverage a case when I have multiple sources to be streamed to different locations.

The main question I have is - what if I want to stream to N different locations from one machine? If the quality of the output will be decreasing when each next process is starting, then it leaves me with running only one process on a machine?

Sorry in case I'm missing something.

Thanks


-----Original Message-----
From: ffmpeg-user <ffmpeg-user-bounces at ffmpeg.org> On Behalf Of Carl Eugen Hoyos
Sent: Friday, March 12, 2021 9:59 AM
To: FFmpeg user questions <ffmpeg-user at ffmpeg.org>
Subject: Re: [FFmpeg-user] How to scale FFmpeg



> Am 12.03.2021 um 08:27 schrieb <imalkevich at gmail.com> <imalkevich at gmail.com>:
> 
> I'm trying to run the following command:

When asking questions on this mailing list, please do not attach screenshots of your console output, instead post the command line you tested (without using the hidebanner option!) together with the complete, uncut console output.

A few random comments:
mpegts and mp4 are not the same things.
You generally cannot request an FPS rate.
When you use the x264 preset „slow“ do not expect it to work in real-time.
There is a tee muxer and it is mentioned in the documentation.

Carl Eugen
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