HOWTO: Proper Screencasting on Linux

**FakeOutdoorsman** · July 28th, 2011

If you want to use the last commit that worked then do:

Code:

sudo apt-get remove ffmpeg
cd ~/ffmpeg
make distclean
git pull
git checkout 8bfd7f6a475225a0595bf657f8b99a8fffb461e4
./configure, make, checkinstall as shown in the FFmpeg compile guide.
make distclean
git checkout master

ron999: I didn't see your last post. Strange. This commit works for me on 32-bit Natty.

**cadens** · July 29th, 2011

Originally Posted by FakeOutdoorsman

If you want to use the last commit that worked then do:

Code:

sudo apt-get remove ffmpeg
cd ~/ffmpeg
make distclean
git pull
git checkout 8bfd7f6a475225a0595bf657f8b99a8fffb461e4
./configure, make, checkinstall as shown in the FFmpeg compile guide.
make distclean
git checkout master

ron999: I didn't see your last post. Strange. This commit works for me on 32-bit Natty.

The following command works for me! Thanks FakeOutdoorsman!

ffmpeg -f alsa -ac 2 -i pulse -f x11grab -r 30 -s 1366x768 -i :0.0 -acodec pcm_s16le -vcodec libx264 -vpre lossless_ultrafast -threads 0 output.mkv

By the way, why have "ctrl+c" to stop screencasting instead of "q"?

**FakeOutdoorsman** · July 29th, 2011

Originally Posted by cadens

By the way, why have "ctrl+c" to stop screencasting instead of "q"?

I blame ffmpeg: get rid of the 'q' key schizofrenia.

I think it's some flotsam that was merged from libav (the FFmpeg fork).

**FakeOutdoorsman** · August 2nd, 2011

Two new x11grab options have been added: follow_mouse and show_region.

Code:

-follow_mouse 100 -show_region 1

From the documentation:

follow_mouse - Only follows when mouse pointer reaches within 100 pixels to the edge of region.
show_region - The grabbing region will be indicated on screen.

If you use both options then, "the grabbing region indication will follow the mouse pointer".

**FakeOutdoorsman** · August 3rd, 2011

Originally Posted by rongden

great guide . I'll test

Are you a robot?

**RottNKorpse** · August 10th, 2011

Originally Posted by verb3k

Example 1:

Code:

ffmpeg -i output.mkv -acodec libfaac -ab 128k -ac 2 -vcodec libx264 -preset slow -crf 22 -threads 0 our-final-product.mp4

In the above example, we encode the audio to AAC at a bitrate of 128k with 2 audio channels (stereo). We encode the video to the high quality H.264 video compression standard. We use the preset "slow" and a CRF value of 22 for rate control. The output file will be named “our-final-product.mp4″ and will be muxed in an .mp4 container. Note that FFmpeg determines the container format of the output file based on the extension you specify (i.e. if you specify the extension as .mkv, your file will be muxed into an .mkv matroska container). You can tweak the CRF value to get different results. The lower you set the CRF value, the better your video’s quality will be, and consequently the file size and encoding time will increase, and vice-versa.

When I tried to use this (Ubuntu 10.10 / ffmpeg SVN-r25943) an error occurred stating "Unrecognized option 'preset'"

I seem to have fixed it though by replacing "-preset" with "-vpre" although I didn't take into account "-apre" so I don't know if leaving that out would cause any issues.

I have tested the final output file when using -vpre and it seems to work fine without utilizing -apre

Hope this helps anyone having the same issue.

**OlympicSoftworks** · August 11th, 2011

Great tutorial

I get magnificent grabs of World of Warcraft with this, and can run them through re-encoding for upload to youtube for my guild. No problemo, but...I cannot find a video editor that reads the raw output of the tutorial's command. I could re-encode it to a lower quality format and then edit it, but that really defeats the purpose.

So, what editor is recommended to edit the raw...or is there a better version of raw to use if editing is desired?

btw, WinFF is also a very nice front-end for anyone not understanding the nuts and bolts of the command line for re-encoding...just sayin.

Thanks for any help on this folks.

**debd** · August 13th, 2011

very nice tutorial ^^

btw.. anybody know how to use the -newaudio option in ffmpeg ??...I mean the syntax sequence? In the man page its not clear :-/

I want to add a new audio stream to a video recorded with -an (no audio).

**Bonster** · September 5th, 2011

Originally Posted by cadens

Hi Ron999!
It's working here with "-acodec flac" instead of "-acodec pcm_s16le".
Thanks!

So the problem is the pcm audio codec?

Thanks i will try flac now

This error only occurs when im using pulse ( -i pulse), with alsa ( -i hw:0,0 ) it runs fine if anyone is wondering.

[matroska @ 0x981a040] Application provided invalid, non monotonically increasing dts to muxer in stream 1: 1 >= 1