Ffmpeg - Revision history

Unknown user: /* Video to images */

2022-05-22T22:44:25Z

Video to images

← Older revision		Revision as of 22:44, 22 May 2022
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	which would yield the files <code>thumb01.jpg,thumb02.jpg,</code> etc...		which would yield the files <code>thumb01.jpg,thumb02.jpg,</code> etc...

	To extract images from the video at a rate, you can use the <code>-r</code> option:		To extract images from the video at a given rate (frames or thumbnails per second), you can use the <code>-r N</code> option. This will output N thumbnails for each second of video.

			For example, to output 2 thumbnails per second of video:

	<pre>		<pre>
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	</pre>		</pre>

	~~which will~~ output ~~2 thumbnails per second~~ of video. This can also be used in combination with <code>-vframes</code> to limit the number of thumbnails saved. Likewise, the option <code>-t N</code> limits thumbnail capturing to N seconds, or <code>-t HH:MM:SS</code> to limit thumbnail capturing for HH hours, MM minutes, and SS seconds.		The rate can also be a fraction. For example, to output 1 thumbnail for every 5 minutes (300 seconds) of video, set the rate to be 1/300:

			<pre>
			ffmpeg -r 1/300 -i movie.mov -f image2 thumb%02d.jpg
			</pre>

			This can also be used in combination with <code>-vframes</code> to limit the number of thumbnails saved. Likewise, the option <code>-t N</code> limits thumbnail capturing to N seconds, or <code>-t HH:MM:SS</code> to limit thumbnail capturing for HH hours, MM minutes, and SS seconds.

	== Video to video ==		== Video to video ==

Unknown user: /* Video to images */

2022-05-22T22:41:03Z

Video to images

← Older revision		Revision as of 22:41, 22 May 2022
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	</pre>		</pre>

	which will output 2 thumbnails per second. This can also be used in combination with <code>-vframes</code> to limit the number of thumbnails saved. Likewise, the option <code>-t N</code> limits thumbnail capturing to N seconds, or <code>-t HH:MM:SS</code> to limit thumbnail capturing for HH hours, MM minutes, and SS seconds.		which will output 2 thumbnails per second of video. This can also be used in combination with <code>-vframes</code> to limit the number of thumbnails saved. Likewise, the option <code>-t N</code> limits thumbnail capturing to N seconds, or <code>-t HH:MM:SS</code> to limit thumbnail capturing for HH hours, MM minutes, and SS seconds.

	== Video to video ==		== Video to video ==

Unknown user: /* Video to images */

2022-05-22T22:40:08Z

Video to images

← Older revision		Revision as of 22:40, 22 May 2022
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	</pre>		</pre>

	which will capture a thumbnail image 3 seconds into the video, using "image2" as the output format (this works for outputting jpg files; set with the <code>-f</code> option), and grabbing only N frames (set with the <code>-vframes N</code> option). If I wanted to grab 5 frames, and create a different image for each, I could issue the command:		which will capture a thumbnail image 3 seconds into the video, using "image2" as the output format (this works for outputting jpg files, but other formats can be set with the <code>-f</code> option), and grabbing only N frames (set with the <code>-vframes N</code> option). If I wanted to grab 5 frames, and create a different image for each, I could issue the command:

	<pre>		<pre>

Unknown user: /* Video to images */

2022-05-22T22:39:29Z

Video to images

← Older revision		Revision as of 22:39, 22 May 2022
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	<pre>		<pre>
	$ ffmpeg -i movie.mpg image%03d.jpg		ffmpeg -i movie.mpg image%03d.jpg
	</pre>		</pre>

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	<pre>		<pre>
	$ ffmpeg -ss 3 -i movie.mov -f image2 -vframes 1 thumb.jpg		ffmpeg -ss 3 -i movie.mov -f image2 -vframes 1 thumb.jpg
	</pre>		</pre>

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	<pre>		<pre>
	$ ffmpeg -ss 3 -i movie.mov -f image2 -vframes 5 thumb%02d.jpg		ffmpeg -ss 3 -i movie.mov -f image2 -vframes 5 thumb%02d.jpg
	</pre>		</pre>

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	<pre>		<pre>
	$ ffmpeg -r 2 -i movie.mov -f image2 thumb%02d.jpg		ffmpeg -r 2 -i movie.mov -f image2 thumb%02d.jpg
	</pre>		</pre>

Unknown user: /* Shortening */

2022-05-21T23:43:11Z

Shortening

← Older revision		Revision as of 23:43, 21 May 2022
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	What if the length of your video and your audio are different? By default, ffmpeg is conservative and doesn't delete anything. The length of the final video will be the length of the longer of the two videos (a three minute video track and a ten minute audio track will result in seven minutes of black screen).		What if the length of your video and your audio are different? By default, ffmpeg is conservative and doesn't delete anything. The length of the final video will be the length of the longer of the two videos (a three minute video track and a ten minute audio track will result in seven minutes of black screen).

	You can tell ffmpeg to ~~shorten~~ the ~~longer one~~ of the two, by using the <code>-shortest</code> flag.		You can tell ffmpeg to trim the length to the shortest of the two, by using the <code>-shortest</code> flag.

	= Gifs =		= Gifs =

Unknown user: /* Shortening */

2022-05-21T23:42:53Z

Shortening

← Older revision		Revision as of 23:42, 21 May 2022
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	What if the length of your video and your audio are different? By default, ffmpeg is conservative and doesn't delete anything. The length of the final video will be the length of the longer of the two videos (a three minute video track and a ten minute audio track will result in seven minutes of black screen).		What if the length of your video and your audio are different? By default, ffmpeg is conservative and doesn't delete anything. The length of the final video will be the length of the longer of the two videos (a three minute video track and a ten minute audio track will result in seven minutes of black screen).

	You can tell ffmpeg to shorten the longer one of the two, by using the <code>-~~shorten~~</code> flag.		You can tell ffmpeg to shorten the longer one of the two, by using the <code>-shortest</code> flag.

	= Gifs =		= Gifs =

Admin: /* Scripts, tricks, and tips */

2018-09-14T00:24:04Z

Scripts, tricks, and tips

← Older revision		Revision as of 00:24, 14 September 2018
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	You can tell ffmpeg to shorten the longer one of the two, by using the <code>-shorten</code> flag.		You can tell ffmpeg to shorten the longer one of the two, by using the <code>-shorten</code> flag.

			= Gifs =

			See [[Gifs]] (specifically the [[Gifs#ffmpeg]] section) for how to use ffmpeg to create/convert gifs.

	= Scripts, tricks, and tips =		= Scripts, tricks, and tips =

Admin: /* Different Resolutions */

2018-02-11T19:45:13Z

Different Resolutions

← Older revision		Revision as of 19:45, 11 February 2018
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	<pre>		<pre>
	ffmpeg~~^Ci~~ maya.mp4 -i cronus.mp4 -filter_complex "[0:v:0]pad=0[bg]; [bg][1:v:0]overlay=w" output.mp4		ffmpeg -i maya.mp4 -i cronus.mp4 -filter_complex "[0:v:0]pad=0[bg]; [bg][1:v:0]overlay=w" output.mp4
	</pre>		</pre>

Admin at 19:44, 11 February 2018

2018-02-11T19:44:49Z

← Older revision		Revision as of 19:44, 11 February 2018
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	[[Category:Video]]		[[Category:Video]]
			[[Category:Ffmpeg]]


	{{Programs}}		{{Programs}}

Admin: /* Combining Videos */

2017-08-14T20:36:14Z

Combining Videos

← Older revision		Revision as of 20:36, 14 August 2017
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	==Combining Videos==		==Combining Videos==

			===Same Resolution===

	If we want to combine two videos and display them side-by-side in-frame, we can use the pad and overlay features. Links:		If we want to combine two videos and display them side-by-side in-frame, we can use the pad and overlay features. Links:
			* ffmpeg pad adds padding to the input image: http://ffmpeg.org/ffmpeg-filters.html#pad
	ffmpeg pad adds padding to the input image: http://ffmpeg.org/ffmpeg-filters.html#pad		* ffmpeg overlay overlays one video on another: http://ffmpeg.org/ffmpeg-filters.html#overlay-1

	ffmpeg overlay overlays one video on another: http://ffmpeg.org/ffmpeg-filters.html#overlay-1

	The basic strategy is to pad the left video with extra spacing on the right side, then overlay the right video in the extra space created.		The basic strategy is to pad the left video with extra spacing on the right side, then overlay the right video in the extra space created.

	<pre>		<pre>
	ffmpeg -i maya.mp4 -i cronus.mp4 -filter_complex "[0:v:0]pad=width=ih*2:ih[bg]; [bg][1:v:0]overlay=w" output.mp4		ffmpeg -i maya.mp4 -i cronus.mp4 -filter_complex "[0:v:0]pad=width=iw*2:ih[bg]; [bg][1:v:0]overlay=w" output.mp4
	</pre>		</pre>

	~~Let's break~~ that command ~~down~~, ~~since~~ it~~'s a bit hairy~~.		The first thing the command does is provide two inputs with the -i flags. Next, the <code>-filter_complex</code> flag will filter/process/combine the inputs and combine them into a single video. Basically we feed filter complex a string, which contains a command that will combine the videos in some particular way.

			The command that is passed to filter_complex starts with <code>[0:v:0]</code> and later has a <code>[1:v:0]</code>, where the left side of the v refers to which input, and the right side of the output refers to which output. In this case we have two inputs, so the 0 and 1 refer to maya.mp4 or cronus.mp4, respectively. There is only one output so we probably don't need the <code>:0</code> at the end, but we add it anyway just to be sure.

	~~The~~ first ~~thing I do~~ is ~~provide~~ two ~~inputs~~, which ~~will be referenced later in~~ the command.		We are telling filter complex to pad the first video by doubling it, and then we overlay the second video. There is a bit of magic [http://www.ffmpeg-archive.org/Merge-two-videos-into-one-with-side-by-side-composition-td4659527.html] happening here, but the <code>[bg]</code> placement tells it which video to put on which side. Finally, we tell the command where to output all of this stuff.

	~~Next,~~ the ~~<code>-filter_complex</code> flag is a general flag for performing any kind of filtering operation (obviously)~~, ~~and is extremely versatile~~.		My final result looked awful because the two videos had completely different resolutions. Thus, I had to make do.

	~~The~~ command ~~that is passed~~ to ~~filter_complex starts with~~ <~~code~~>[0:v:0]~~</code> and later has a <code>~~[1:v:0]</~~code~~>~~, where the left side of the v refers~~ to ~~which input, and the right side of~~ the output ~~refers to which output. In this case we have two inputs, so the 0 and 1 refer to maya.mp4 or cronus.mp4, respectively. There is only one output so we probably don't need the <code>~~:0</~~code> at the end, but we add it anyway just to be sure~~.		===Different Resolutions===

			I had a high-resolution and a low-resolution video, and didn't want to reduce the resolution of both to be poor, so I modified the above overlay command to eliminate the padding:

			<pre>
			ffmpeg^Ci maya.mp4 -i cronus.mp4 -filter_complex "[0:v:0]pad=0[bg]; [bg][1:v:0]overlay=w" output.mp4
			</pre>

			This led to the following video output: https://vimeo.com/229620373

	=Flags=		=Flags=