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. Note that 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 is RGB, then you may choose the video codec libx264rgb rather than libx264. The video codec is specified by -codec:video, which is usually abbreviated as -c:v ( -codec:v or -c:video are also possible). And for image sequences starting at 086400 (captured at 24 fps with a timecode starting at 01:00:00:00) or at 090000 (captured at 25 fps with a timecode starting at 01:00:00:00), add the flag -start_number 86400 or -start_number 90000 before -i input_file_%06d.ext. The command must of course match the naming convention actually used.
YUV VIDEO SEQUENCES FULL
This allows to read in ascending order, one image after the other, the full sequence inside one folder. The regex %06d matches six digits long numbers, possibly with leading zeroes. The frame rate of sound film is 24 fps (frames per second) and the default frame rate of image2 is 25 fps, therefore we have to change it. Therefore the option -f image2 must precede the image sequence given as input. The parameters witch apply to the input files must precede them.
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.
pix_fmt yuv420p \ output_file Command syntax ffmpeg starts the command -f image2 forces the image file de-muxer for single image files -framerate frames_per_second sets the frame rate -i input_file_regex.ext path, name with regex and extension of the input files -c:v libx264 The library libx264 re-encodes the video stream using the H.264 video codec. pix_fmt yuv420p \ output_file General command ffmpeg \ Transcode an image sequence by using the H.264 codec for dissemination purposes. Image sequence into H.264 / MPEG-4 AVC Problem
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