Re: HOWTO: Proper Screencasting on Linux
Oh, thank you so much for the tutorial!! I wanted to do screencasting for a long time now and when I finally found something I could really use it for (pitching a solution for sharing pictures that is made at our education, with the use of gallery3) I stumbled upon this tutorial.
As I want to use open source solutions regardless of a whatever lack of quality as long as it's getting the point across this worked out beautifully. I didn't experience a lack of quality in the .ogg end result at all actually.. I was surprised the 'lossless' .mkv file went from 100mb to only 60mb in the .ogg result..
Btw; I anticipated that explaining how to use program you don't need 30fps, so I set it to 23fps which was fine..
Re: HOWTO: Proper Screencasting on Linux
You can encode to the new open format "WebM", which should give you much better quality than .ogg with Theora. Just replace libtheora with libvpx (assuming you followed the ffmpeg building guide, you should have that included as well) and encode the file in 2 passes with the -pass 1/2 option. Also, change the extension to .webm instead of .ogg.
Example:
Pass 1:
Code:
ffmpeg -i output.mkv -an -vcodec libvpx -b 1000k -pass 1 our-final-product.webm
Pass 2:
Code:
ffmpeg -i output.mkv -acodec libvorbis -ab 128k -ac 2 -vcodec libvpx -b 1000k -threads 2 -pass 2 our-final-product.webm
Change the bitrate (-b 1000k) to control the size/quality tradeoff. Also, change the number of threads (-threads 2) to suit the number of threads your CPU has. If your CPU is not multi-threaded, you can omit the -threads option completely. If you have a modern web browser, you can open the file and play it natively inside it. A WebM file consists of VP8 video and Vorbis audio mulitplexed into a .webm container (which is basically a subset of the Matroska container, aka .mkv).
Re: HOWTO: Proper Screencasting on Linux
Guide update: Added WebM example, updated the guide to reflect the change from "q" to "ctrl-c" to stop recording.
How2 stop ffmpegs x11grab grabbing the mouse cursor ?
Hi there,
I've been searching this thread and read various postings in the www but didn't find a real answer to my issue.
It has been awhile since I captured some gaming videos under Linux with ffmpeg but on my newly set up Ubuntu 10.04 x64 box ffmpeg (with x11grab) records an ugly white mouse cursor in the middle of the screen even if no cursor should be visibile (e.g. playing Q3A in fullscreen mode).
On the same system with archlinux x64 I never experience such behaviour. Of course it is possible that this was an older version of ffmpeg which didn't capture mouse pointers at all ?
Is there an option to disable any mouse cursor capturing ?
Edit: I would be fine with rebuilding ffmpeg from source.
TIA,
Holger
P.S.: A small note to those who experience audio delay with ffmpeg and PA. I found out that my system produces a constant delay of 2100 ms. If I resync audio and video afterwards by this value everything is perfectly in sync.
Re: How2 stop ffmpegs x11grab grabbing the mouse cursor ?
Quote:
Originally Posted by
HolgerB
Is there an option to disable any mouse cursor capturing ?
There is a nomouse option:
Works with FFmpeg from the repository for Maverick at least.
Re: How2 stop ffmpegs x11grab grabbing the mouse cursor ?
Quote:
Originally Posted by
FakeOutdoorsman
There is a
nomouse option:
Works with FFmpeg from the repository for Maverick at least.
Awesome. Works on git FFmpeg too. NB4 I add it to the guide.
Thanks.
EDIT: Added. Thanks again.
Re: How2 stop ffmpegs x11grab grabbing the mouse cursor ?
Quote:
Originally Posted by
FakeOutdoorsman
There is a
nomouse option:
Works with FFmpeg from the repository for Maverick at least.
Thanks for your hint but at least my version SVN-r0.5.1-4:0.5.1-1ubuntu1.1 does not seem to care :lolflag:
1 Attachment(s)
Re: HOWTO: Proper Screencasting on Linux
I've had some experience with gtk-recordMyDesktop, but after I switched from a 32-bits desktop pc to a 64-bits laptop (Ubuntu 10.10), RMD started performing badly: The last part of the captured video does not show up in the final ogv video:confused:
I tried ffmpeg using this and many other guides, without the expected/promised result. You're claiming a zero-quality loss, although I experience the opposite: see attachment.
The upper part of the screenshot shows the original sample, the bottom part shows the result after capturing: A very perceivable result. The colors are different, and some particles are faded.
How can I capture a part of my screen without any loss in quality? I want to edit the captured screen using Kdenlive, then upload it to YouTube (using h.264).
I used the following code:
Code:
ffmpeg -f x11grab -r 15 -s 768x512 -i :0.0+810,55 -vcodec libx264 -vpre lossless_ultrafast -threads 0 /tmp/ffmpeg-tests/out.mkv
I tried all possible vpre options and over twenty file extensions, yet no satisfying result. Could anyone help me with solving this extremely annoying issue?
Re: HOWTO: Proper Screencasting on Linux
Quote:
Originally Posted by
M759
I my screen without any loss in quality? I want to edit the captured screen using Kdenlive, then upload it to YouTube (using h.264).
I would go for huffyuv for video codec which is lossless. Audio could be plain pcm or flac.
You should always check out the captured video in mplayer or vlc if you experience image corruption in kdenlive or any other video editing software.
I can post my ffmpeg rec command this evening if you like.
Re: HOWTO: Proper Screencasting on Linux
Quote:
Originally Posted by
M759
I've had some experience with gtk-recordMyDesktop, but after I switched from a 32-bits desktop pc to a 64-bits laptop (Ubuntu 10.10), RMD started performing badly: The last part of the captured video does not show up in the final ogv video:confused:
I tried ffmpeg using this and many other guides, without the expected/promised result. You're claiming a zero-quality loss, although I experience the opposite: see attachment.
The upper part of the screenshot shows the original sample, the bottom part shows the result after capturing: A very perceivable result. The colors are different, and some particles are faded.
How can I capture a part of my screen
without any loss in quality? I want to edit the captured screen using Kdenlive, then upload it to YouTube (using h.264).
I used the following code:
Code:
ffmpeg -f x11grab -r 15 -s 768x512 -i :0.0+810,55 -vcodec libx264 -vpre lossless_ultrafast -threads 0 /tmp/ffmpeg-tests/out.mkv
I tried all possible vpre options and over twenty file extensions, yet no satisfying result. Could anyone help me with solving this extremely annoying issue?
This is probably because libx264 does not yet support the 4:4:4 color space; edges of very small and sharp lines might appear a bit blurred. Go ask the x264 developers to add it.