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• What are all the command `options` to execute with ?

  25 janvier 2023, par Phil Lucks

  I'd like to be able to compress the video in a way to help improve upload times.

  


  In reading the docs for FFMpeg Kit, using React Native, there is a basic execute command string of '-i file1.mp4 -c:v mpeg4 file2.mp4'... I can guess at what some of this means, in terms of input & output file names based on the ffMPEG docs, however, some of these options I am not sure of.

  


  Like why is there a -i flag prefix ? Is this "input" ?
Why is there -c:v ? Is this "convert video" ?
What if I want to reduce frame rate, or change size of video ?

  


  The TS def is just a string...

  


  Is there a good place to understand what the official docs options map to the strings ? I think

  


• Encoding rawframes to raw h264 live [closed]

  25 juillet 2024, par Enry Frafranci

  I'm trying to make an application that generates an mp4 stream live in node.js.

  


  So far I've successfully got the stream part working with static pre-encoded raw h264 files, then passing them trough jmuxer, streaming it to an express endpoint.
Now I would like to generate live the h264 stream based on a canvas that gets drawn live.
I've managed to use the canvas module to do that with no issue, but problems arise when trying to compress and encode the canvas output with ffmpeg. This is the command that I'm running, while piping in the raw video frames, and expecting on the pipe output the raw h264 stream :

  


  ffmpeg -f rawvideo -r 30 -pixel_format rgb24 -video_size 640x480 -i pipe:0 -c:v libx264 -pixel_format yuv420p -preset fast -f h264_mp4toannexb pipe:1


  


  But this is the error message I receive instead :

  


  Output format h264_mp4toannexb is not available


  


  I know for sure my frame generation works correctly and ffmpeg accepts it because a previous project of mine used basically the same exact code, with the exception of the output being a simple mp4 file and not a stream.

  


  Any help to figure out what's a good solution is appreciated !

  


  Thanks

  


  Rico

  


• Lossless Video Compression formats

  26 novembre 2019, par jippyjoe4

  I create lots of 4K 60fps 3D animations, and every frame of these animations are exported as separate PNG files to my disk drive. These PNG files use their own lossless compression method, but the file sizes are still quite large (a 30 second animation can take anywhere between 4 and 18 GB). I’m interested in alternative lossless compression formats to reduce the file sizes even further.

  The reason I’m interested in lossless compression is because I create a LARGE variety of animations, and lossy algorithms are not always consistent in terms of visual fidelity (what doesn’t create visible artifacts for one animation might for another).

  Do you have good recommendations for general purpose lossless video codecs that can achieve superior performance to storing the PNG frames individually ?

  So far, I have attempted to use h.265 lossless using ffmpeg :

  ffmpeg -r 60 -i out%04d.png -c:v libx265 -preset ultrafast -x265-params lossless=1 OUTPUT.mp4

  But the result was a 15.4GB file when the original PNG files themselves only took up 5.77 GB in total. I assume this was because, for this particular animation, interframe compression was far worse than intraframe compression, but I don’t really know.

  I understand that this is highly dependent on the content I’m attempting to compress, but I’m just hoping that I can find something that’s better than storing the frames individually.