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When to use a scale filter in FFmpeg?
If you need to simply resize your video to a specific size (e.g 320×240), you can use the scale filter in its most basic form: Same works for images too: The resulting image will look like this: As you can see, the aspect ratio is not the same as in the original image, so the image appears stretched.
How many audio channels are there in FFmpeg?
Audio sample rate is always 48 kHz and the number of channels can be 2, 8 or 16. Note that all audio channels are bundled in one single audio track. If set to true, print a list of devices and exit. Defaults to false.
How is the min function used in FFmpeg?
This can be done using min expressions: The output width will be evaluated to be the minimum of 320 and the input width. If you have an imput image that is only 240 pixels wide, the result of the min function will be 240 – this will be your target value.
How to calculate the target bitrate for FFmpeg?
You calculate your target bitrate using bitrate = file size / duration and you launch ffmpeg two times: one pass analyzes the media and the second does the actual encoding: Edit: H.265 (HEVC) is even better at compression (50% of H.264 size in some cases) but support is not yet widespread so stick with H.264 for now.
How does FFmpeg change the aspect ratio of a video?
For reasons not completely understood, FFMPEG monkeys around with the Sample/Pixel Aspect Ratio to turn the video back to the original aspect ratio. For instance, if you stretch the video out twice as wide, it will make the aspect ratio 1:2, or something similar (2:1?)
How to do a scene change detection with ffmpeg?
– Stack Overflow Using FFMPEG: How to do a Scene Change Detection? with timecode? Based on this article it seems that it is possible to use FFMPEG to detect scene change in videos: http://www.luckydinosaur.com/u/ffmpeg-scene-change-detector
How to find the optimal threshold in FFmpeg?
You can try to find an optimal threshold by extracting frames for different thresholds (and afterwards examine the frames manually) like this Just for clarification: grep [0-9.]* does not exclude integers as claimed in another answer.
Is there way to force color range in FFmpeg?
The output range can be forced, as can the color range metadata, but your player or editor may force a limited range interpretation, So, caveat transcoder. With that said, you have to set two flags: first one for the scaler, and then for the metadata.
Do you need FFmpeg for HEVC encoded video?
FFmpeg may be built for 8-bit colors or for 10-bit colors, or — in recent time — for both of them (for your HEVC encoded video). So you need to build (or obtain by other way) version for 8-/10- or 10-bit color depth.
Is there a way to get Black Blacks in FFmpeg?
So, are there any FFMPEG gurus out there that can give me the magic switches to get my output movies with black blacks and colors that maintain the original frame files 0-255 RGB values. The output range can be forced, as can the color range metadata, but your player or editor may force a limited range interpretation, So, caveat transcoder.