Wiki source code of Video Capture of Computer Screens

Last modified by Drunk Monkey on 2024-10-09 05:32

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1.1	1	{{box cssClass="floatinginfobox" title="Contents"}}
1.3	2	{{toc depth="3" start="2" numbered="true"/}}
1.1	3	{{/box}}
	4
	5	== Required Programs ==
	6
	7	1. [[VLC Media Player>>https://www.videolan.org/vlc/]] - required for playback of just about any kind of video content you can imagine
5.1	8	1. [[7-zip>>https://www.7-zip.org]] - you will need this to extract the contents of the FFmpeg files, which are stored as a 7z archive. Mac OSX will use [[Keka>>https://www.keka.io/en/]]
1.1	9	1. [[FFmpeg>>http://ffmpeg.org/download.html]] - the ultimate Swiss Army Knife multitool of multimedia encoding/decoding
	10
	11	== Installation ==
	12
	13	1. VLC installs are straight forward. Run the installer and you're done.
	14	1. FFmpeg is a bit more complicated, and it depends on your platform.
	15
3.1	16	----
1.1	17
	18	(% class="row" %)
	19	(((
3.1	20	(% class="col-xs-12 col-xs-6" style="border-right:black solid 1px;" %)
1.1	21	(((
1.2	22	=== Windows ===
3.1	23
5.1	24	1. Run the VLC installer
27.1	25
5.1	26	1. Install 7-zip
27.1	27
26.1	28	1. Extract the contents of the FFmpeg zip file into a suitable directory. I going to use C:\Local\ffmpeg\ as my FFmpeg installation location for this example. You should see something similar to this:
27.1	29	[[image:image-20220127221835-1.png]]
	30	\\The contents of the ffmpeg filder should look like this:
18.2	31	[[image:image-20220127225738-2.png]]
	32	\\Select all the files and move them into the installation directory. That is C:\Local\ffmpeg\ in this example.
	33	[[image:image-20220127225847-3.png]]
3.1	34
18.2	35	1. Next, add the location of the ffmpeg\bin directory to the system path. This is necessary so you can run the command from the command line from a command shell.
	36	\\Go to the file explorer, and look in the left hand folder list for "This PC" or "My PC" or whatever it is called on your system.
	37	[[image:image-20220127230601-5.png]]
	38	\\When you find it, right click in it to bring up the local context menu and select Properties
	39	[[image:image-20220127230404-4.png]]
	40	\\In newer versions of Windows, the properties page looks like this:
	41	[[image:image-20220127230803-6.png]]
	42	\\Look for the "Advanced system settings" (right middle in the above screenshot) and click on it
	43	[[image:image-20220127230949-7.png]]
	44	\\Select "Environment Variables" and the following screen will appear
	45	[[image:image-20220127231106-8.png]]
	46	\\In the top half of the User variables section is an entry called "Path". Select it and click on "Edit". Do not edit the path of the System variables section unless you know what you are doing.
	47	[[image:image-20220127231323-9.png]]
	48	\\Click on "New" and add the following "C:\Local\ffmpeg\bin"
	49	[[image:image-20220127231805-12.png]]
	50	\\and then click on the "Move up" button until that new entry appears at the top of the list
	51	[[image:image-20220127231836-13.png]]
	52	\\Click on OK, and ffmpeg will be available for use on the command line.
	53	[[image:image-20220127232109-14.png]]
	54	\\Click on OK to close the Environment Variables settings, and then click on OK to close the System Properties.
22.1	55
	56	1. Start a command line window by typing cmd.exe into the search bar and open the Command Prompt
	57	[[image:image-20220127232411-15.png]]
	58
	59	1. in that command prompt, type in "ffmpeg" and you should see this:
	60	[[image:image-20220127232635-16.png]]
	61	\\If you get an error like this, either you typed in the command incorrectly (as I did in the following example) or you did not configured your user path correctly and you have to go back and correct it
	62	[[image:image-20220127232731-17.png]]
22.2	63	\\You are now ready to capture video
18.2	64	)))
	65
1.1	66	(% class="col-xs-12 col-xs-6" %)
	67	(((
1.2	68	=== Mac OSX ===
5.1	69
	70	1. Install VLC
28.1	71
5.1	72	1. Install Keka
28.1	73
	74	1. Install FFmpeg through the use of [[HomeBrew>>https://brew.sh]] (recommended because of all the other useful things you can install if you like this kind of stuff) or install the statically linked binary version of the [[FFmpeg binaries>>http://ffmpeg.org/download.html]] from [[https:~~/~~/evermeet.cx/ffmpeg/>>https://evermeet.cx/ffmpeg/]]. This file will need to be placed into a directory that's on your path (not yet described how to do)
	75	\\The statically linked installation is going to be faster and easier to do than the homebrew version.
1.1	76	)))
	77	)))
	78
24.1	79	----
	80
24.2	81	== Video Capture ==
24.1	82
	83	----
	84
23.1	85	(% class="row" %)
	86	(((
	87	(% class="col-xs-12 col-xs-6" style="border-right:black solid 1px;" %)
	88	(((
31.1	89	=== Windows ===
3.1	90
22.2	91	Open a command window, and run the following commands:
	92
	93	>(% style="font-size:14px" %)cd Desktop
	94	>(% style="font-size:14px" %)ffmpeg -f gdigrab -t 6 -draw_mouse 1 -framerate 60 -i desktop -c:v libx264rgb -crf 0 -preset ultrafast screenCapture.mkv
	95
	96	(% style="font-size:14px" %)This will create a video file called "screenCapture.mkv" on your desktop that you can replay using VLC Media Player.
	97
28.1	98	(% style="font-size:14px" %)The parameters to the ffmpeg command have the following meanings
22.2	99
30.1	100	(% class="grid min" %)
22.2	101	\|-f gdigrab\|gdigrab is the windows framebuffer, where the screen is stored
28.2	102	\|-t 6\|capture 6 seconds of video and exit. 3600 = 1 hour, 14400 = 4 hours. If you omit this parameter, the capture will continue until you press [Control C] to gracefully tell ffmpeg to stop
28.1	103	\|(% style="font-size:14px" %)-framerate 60\|if you want to see the candles paint second by second, you should have a framerate of at least 60. Technically speaking, you actually need 120, but let's not get too crazy.
22.2	104	\|-draw_mouse 1\|capture the mouse pointer
	105	\|-i desktop\|capture the entire desktop - remember to maximize your window
	106	\|-c:v libx264rgb\|this video encoder will preserve the rgb color values losslessly
	107	\|-crf 0\|lossless compression
	108	\|-preset ultrafast\|save the data as quickly as possible, don't waste too much time compressing the data
24.3	109
	110	If you want to save the for long term storage, you can losslessly compress the file even further with the following command
	111
	112	>(% style="font-size:14px" %)fmpeg -i screenCapture.mkv -c:v libx264rgb -crf 0 -preset veryslow screenCaptureS.mkv
	113
25.1	114	It'll take a while, but it will create a video file that should be less than half the size of the original.
23.1	115	)))
22.2	116
23.1	117	(% class="col-xs-12 col-xs-6" %)
	118	(((
31.1	119	=== Mac OSX ===
24.3	120
28.1	121	Open a terminal window and run the following commands:
24.3	122
33.1	123	>(% style="font-size:14px" %)cd ~~/Desktop
	124	>(% style="font-size:14px" %)ffmpeg -f avfoundation -t 6 -pixel_format 0rgb -capture_cursor 1 -capture_mouse_clicks 1 -framerate 60 -i "1:" -filter:v "format=yuv444p" -c:v libx265 -crf 0 -preset ultrafast screenCapture.mkv
28.1	125
	126	(% style="font-size:14px" %)This will create a video file called "screenCapture.mkv" on your Desktop that you can replay using VLC Media Player.
	127
	128	(% style="font-size:14px" %)The parameters to the ffmpeg command have the following meanings
	129
31.1	130	(% class="lined min" %)
28.1	131	\|-f avfoundation\|gdigrab is the windows framebuffer, where the screen is stored
28.2	132	\|-t 6\|capture 6 seconds of video and exit. 3600 = 1 hour, 14400 = 4 hours. If you omit this parameter, the capture will continue until you press [Control C] to gracefully tell ffmpeg to stop
28.1	133	\|(% style="font-size:14px" %)-framerate 60\|if you want to see the candles paint second by second, you should have a framerate of at least 60. Technically speaking, you actually need 120, but let's not get too crazy.
	134	\|-pixel_format 0rgb\|get the data as RGB colors instead of some bizzzare color model
	135	\|-capture_cursor 1\|capture the mouse pointer
	136	\|-capture_mouse_clicks 1\|and capture the clicks with an onscreen visual notification
33.1	137	\|-i "1:"
	138	\\\\-i title="window title"\|(((
36.1	139	capture the first screen. Not really important unless you have multiple screens and you are not capturing the primary screen. Use '##ffmpeg -f avfoundation -list_devices true -i ""##' to list the capturable devices on your computer
33.1	140	\\to capture a particular window
	141	)))
28.1	142	\|-filter:v "format=yuv444p"\|transform the input colors into this color format, which is fairly quick when converting from RGB and without too much color shifting
	143	(I'm still looking to improve upon this - the windows encoding has an exact RGB color modelling which means no color shift)
	144	\|-c:v libx265\|encode the video using H.265 compression. It makes for smaller videos without consuming too much processing time
	145	\|-crf 0\|lossless compression
	146	\|-preset ultrafast\|save the data as quickly as possible, don't waste too much time compressing the data.
	147
	148	There is no point in trying to compress this video any further with these parameters. Further compression will require a lot of time and cpu power to see any further gain.
24.2	149	)))
	150	)))
32.1	151
32.2	152	== Audio Capture ==
32.1	153
32.2	154	=== Windows ===
	155
	156	=== Mac OSX ===
	157
	158
	159	== References ==
	160
32.1	161	FFmpeg documentation:
	162
	163	* [[https:~~/~~/ffmpeg.org/documentation.html>>https://ffmpeg.org/documentation.html]]
	164
	165	Lossless capture:
	166
	167	* [[https:~~/~~/video.stackexchange.com/questions/25034/lossless-capture-with-ffmpeg>>https://video.stackexchange.com/questions/25034/lossless-capture-with-ffmpeg]]
	168	* [[https:~~/~~/video.stackexchange.com/questions/8305/lossless-screen-recording-software>>https://video.stackexchange.com/questions/8305/lossless-screen-recording-software]]
	169	* [[https:~~/~~/trac.ffmpeg.org/wiki/Capture/Desktop>>https://trac.ffmpeg.org/wiki/Capture/Desktop]]
	170
33.1	171	Video editing programs
	172
	173	* black magic davinci resolve
	174	* kdenlive
	175	* shotcut
	176
34.1	177	== Tips ==
	178
	179	Screen capture portion of a screen
	180
	181	>(% style="font-size:14px" %)ffmpeg -y -f avfoundation -t 6 -pixel_format 0rgb -capture_cursor 1 -capture_mouse_clicks 1 -framerate 60 -i "1:" -filter:v "format=yuv444p" -filter:v "crop=1920:1080:320:180" -c:v libx265 -crf 0 -preset ultrafast screenCapture.mkv
	182
35.1	183	(% style="font-size:14px" %)extract audio
	184
	185	(% style="font-size:14px" %)ffprobe <videofile> to determine the audio format
	186
	187	(% style="font-size:14px" %)ffmpeg -i <filename> -y -ss 01:50:47.0 -t 0:02:03 -vn -c:a copy <outputaudio>.aac (assuming audio is aac as determined by ffprobe above)
	188
	189
32.1	190