Ffmpeg encode yuv to h2645/9/2023 Many of the non-FFmpeg-based players cannot decode H.264 files having a different chroma subsampling than 4:2:0. This can result in the “YUV” colour space with 4:4:4 or 4:2:2 or 4:2:0 chroma subsampling. The library libx264 supports both, but you cannot combine 8-bit and 10-bit in the same command, you need two commands.īy default the library libx264 will use the chroma subsampling scheme that matches closest the input file’s chroma subsampling. Yuv420p is a common 8-bit and yuv420p10le a 10-bit pixel format. Most of the non-FFmpeg-based players cannot decode H.264 files holding lossless content. The range of the scale for crf and qp for 8-bit is from 0 to 51, where 0 is lossless, approximately 18 is “visually lossless”, 23 is the default value and 51 is worst possible. You can use the parameter -qp 18 (quantisation parameter) rather than -crf 18 (constant rate factor) which gives a similar “visually lossless” result. Slower encoding means that more time is needed, but the compression rate is better. Possible -preset values for the H.264 codec include veryslow, slow, medium, fast and veryfast. If the source should be RGB, then you might choose the video codec libx264rgb rather than libx264. The video codec is specified by -codec:video, which may be abbreviated as -c:v (or -codec:v or -c:video). c:a copy re-encodes the audio stream using the same audio codec output_file path, name and extension of the output file Discussion pix_fmt yuv420p The pixel format for “YUV” colour space with 4:2:0 chroma subsampling and planar colour alignment is chosen for best compatibility. crf constant_rate_factor A parameter of 18 means a “visually lossless” compression. preset preset_value A slower encoding preset means a better compression rate. c:a copy \ output_file Command syntax ffmpeg starts the command -i input_file path, name and extension of the input file -c:v libx264 The library libx264 re-encodes the video stream using the H.264 video codec. c:a copy \ output_file Generic command ffmpeg \ Transcode a video file by using the H.264 codec for dissemination purposes.
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