[LAU] Screencasting with JACK [SOLVED!]

Previous message: [thread] [date] [author]
Next message: [thread] [date] [author]
To: linux-audio-user <linux-audio-user@...>, lad <linux-audio-dev@...>
Date: Friday, August 9, 2013 - 1:54 am

--089e014949921f874304e37a0e5c
Content-Type: text/plain; charset=UTF-8

As some of you may recall, every time I've posted a demo video to LAD, I've
had to include a disclaimer excusing the poor quality due to a lack of
functional screencasting tools.

Well, it took a couple of weeks of hair pulling and many, many hours of
testing, but I finally arrived at a solution.

Anyone who wants to create a screencast and record audio via JACK *in
perfect sync* must do the following:

Get ffmpeg. Apply this patch to it:

https://github.com/original-male/FFmpeg/commit/d02509d04d396a98646ca81e9...

Build it with vorbis and h264 support.

Then, start your favorite desktop environment. I use Xephyr for this.

Have jack running (at -r 48000)

Then run the following command:

ffmpeg -fflags +genpts+igndts -f x11grab -vsync 0 -r 30 -s 1920x1080 -i
:${DISPLAY}.+0,0 -vcodec h264 -f jack -ac 2 -r:a 48000 -i screencast
-acodec pcm_s16le -r:v 30 -vsync 2 -async 1 -map 0:0,1,0 -map 1:0 -preset
ultrafast -qp 0 "$FILE"

Where DISPLAY is the number of your X11 display and FILE is the filename
for the screencast. I use a .mkv extension for the matroska container.

Remember to connect the streams you want recorded to the 'screencast' JACK
inputs!

With this setup I'm able to record a full 30 FPS @ 1080P with audio in
perfect sync. Please share your results too. With some more evidence I
might have a good case to get ffmpeg to accept my patch.

Enjoy!

--089e014949921f874304e37a0e5c
Content-Type: text/html; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

As some of you may recall, every =
time I've posted a demo video to LAD, I've had to include a disclai=
mer excusing the poor quality due to a lack of functional screencasting too=
ls.
Well, it took a couple of weeks of hair pulling and many, many ho=
urs of testing, but I finally arrived at a solution.Anyone wh=
o wants to create a screencast and record audio via JACK *in perfect sync* =
must do the following:
Get ffmpeg. Apply this patch to it:https://github.com/original-male/FFmpeg/commit/d025=
09d04d396a98646ca81e9ba327a501486130.patch

Build it with vorbis and h264 support.The=
n, start your favorite desktop environment. I use Xephyr for this.<=
/div>Have jack running (at -r 48000)Then run the fo=
llowing command:
ffmpeg -fflags +genpts+igndts -f x11grab -vsync 0 -r 30 -s 1920x1080 -i=
:${DISPLAY}.+0,0 -vcodec h264 -f jack -ac 2 -r:a 48000=C2=A0 -i screencast=
-acodec pcm_s16le -r:v 30 -vsync 2 -async 1 -map 0:0,1,0 -map 1:0 -preset =
ultrafast -qp 0 "$FILE"
Where DISPLAY is the number of your X11 display and FILE is =
the filename for the screencast. I use a .mkv extension for the matroska co=
ntainer.Remember to connect the streams you want recorde=
d to the 'screencast' JACK inputs!
With this setup I'm able to record a full 30 FPS @ 1080P=
with audio in perfect sync. Please share your results too. With some more =
evidence I might have a good case to get ffmpeg to accept my patch.
Enjoy!

--089e014949921f874304e37a0e5c--

Previous message: [thread] [date] [author]
Next message: [thread] [date] [author]

Messages in current thread:
[LAU] Screencasting with JACK [SOLVED!], J. Liles, (Fri Aug 9, 1:54 am)
Re: [LAU] [LAD] Screencasting with JACK [SOLVED!], Diego Simak, (Sun Aug 11, 1:19 pm)
Re: [LAU] [LAD] Screencasting with JACK [SOLVED!], Peder Hedlund, (Mon Aug 12, 8:38 am)
Re: [LAU] [LAD] Screencasting with JACK [SOLVED!], Diego Simak, (Mon Aug 12, 12:18 pm)
Re: [LAU] [LAD] Screencasting with JACK [SOLVED!], J. Liles, (Mon Aug 12, 4:21 pm)
Re: [LAU] [LAD] Screencasting with JACK [SOLVED!], J. Liles, (Mon Aug 12, 2:19 am)
Re: [LAU] [LAD] Screencasting with JACK [SOLVED!], Harry van Haaren, (Fri Aug 9, 8:03 pm)
Re: [LAU] Screencasting with JACK [SOLVED!], J. Liles, (Fri Aug 9, 2:59 am)