How do I add a custom thumbnail to a .mp4 file using ffmpeg?
Using ffmpeg 4.0, released Apr 20 2018 or newer, ffmpeg -i video.mp4 -i image.png -map 1 -map 0 -c copy -disposition:0 attached_pic out.mp4
video-processing
How to detect if a video file was recorded in portrait orientation, or landscape in iOS
Based on the previous answer, you can use the following to determine the video orientation: + (UIInterfaceOrientation)orientationForTrack:(AVAsset *)asset { AVAssetTrack *videoTrack = [[asset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0]; CGSize size = [videoTrack naturalSize]; CGAffineTransform txf = [videoTrack preferredTransform]; if (size.width == txf.tx && size.height == txf.ty) return UIInterfaceOrientationLandscapeRight; else if (txf.tx == 0 && txf.ty == 0) return … Read more
Extracting DCT coefficients from encoded images and video
Well, I did a bit of reading and my original question seems to be an instance of wishful thinking. Basically, it’s not possible to get the DCT coefficients from H.264 video frames for the simple reason that H.264 doesn’t use DCT. It uses a different transform (integer transform). Next, the coefficients for that transform don’t … Read more
Fetching the dimensions of a H264Video stream
NO!!! You must run a complex function to extract video dimensions from Sequence Parameter Sets. How to do this? Well first you must write your own Exp-Golomb decoder, or find one online… in live555 source code somewhere there is one for example… Then you must get one SPS frame. It has NAL=0x67 (NAL is the … Read more
How can I extract audio from video with ffmpeg?
To extract the audio stream without re-encoding: ffmpeg -i input-video.avi -vn -acodec copy output-audio.aac -vn is no video. -acodec copy says use the same audio stream that’s already in there. Read the output to see what codec it is, to set the right filename extension.
Solid FFmpeg wrapper for C#/.NET
This is a wrapper of my own: https://github.com/AydinAdn/MediaToolkit MediaToolkit can: Convert video files into various other video formats. Perform video transcoding tasks. Options configurable: Bit rate, Frame rate, Resolution / size, Aspect ratio, Duration of video Perform audio transcoding tasks. Options configurable: Audio sample rate Convert video to physical formats using FILM, PAL or NTSC … Read more
Post processing in ffmpeg to move ‘moov atom’ in MP4 files (qt-faststart)
Seems like faststart support has been included in ffmpeg. FFmpeg Formats Documentation: -movflags faststart Run a second pass moving the moov atom on top of the file. This operation can take a while, and will not work in various situations such as fragmented output, thus it is not enabled by default.
Rotating videos with FFmpeg
Rotate 90 clockwise: ffmpeg -i in.mov -vf “transpose=1” out.mov For the transpose parameter you can pass: 0 = 90CounterCLockwise and Vertical Flip (default) 1 = 90Clockwise 2 = 90CounterClockwise 3 = 90Clockwise and Vertical Flip Use -vf “transpose=2,transpose=2” for 180 degrees. Make sure you use a recent ffmpeg version from here (a static build will … Read more
Vertically or horizontally stack (mosaic) several videos using ffmpeg? [closed]
Use the vstack (vertical), hstack (horizontal), or xstack (custom layout) filters. It is easier and faster than other methods. Combine/stack two videos or images Vertical Using the vstack filter. ffmpeg -i input0 -i input1 -filter_complex vstack=inputs=2 output Videos must have the same width. Horizontal Using the hstack filter. ffmpeg -i input0 -i input1 -filter_complex hstack=inputs=2 … Read more