lygbuaa/make_dataset

ffmpeg tools

ffmpeg clip video

ffmpeg -i input.mkv -ss 0:13 -t 6 -c:v libx265 output.mkv #start from 0:13, clip 6secs, H265 output

支持的像素格式

ffmpeg -pix_fmts

抽帧 This will extract one video frame per 20 second from the video and will output them in files named foo-001.jpeg,

foo-002.jpeg, etc. Images will be rescaled to fit the new WxH values.

Incompatible pixel format 'uyvy422' for codec 'mjpeg', auto-selecting format 'yuvj420p'

ffmpeg -i sample.mkv -r 0.05 -s 3840x2160 -f image2 -pix_fmt yuvj444p sample_%03d.jpg

jpg to nv12

ffmpeg -i sample_001.jpg -pix_fmt nv12 sample_001.yuv

jpg to h265

ffmpeg -framerate 1 -i sample_001.jpg -c:v libx265 -crf 15 -preset ultrafast -pix_fmt nv12 -c:a copy sample_frame_001.mkv

nv12 to h265

ffmpeg -framerate 1 -f rawvideo -pix_fmt nv12 -video_size 3840x2160 -i sample_001.yuv -c:v libx265 -crf 15 -preset ultrafast -pix_fmt nv12 -c:a copy sample_frame_nv12.mkv

uyvy to nv12

ffmpeg -f rawvideo -pix_fmt uyvy422 -video_size 3840x2160 -i 8m.uyvy -pix_fmt nv12 8m.yuv

nv12 to uyvy

ffmpeg -f rawvideo -pix_fmt nv12 -video_size 3840x2160 -i 8m.nv12 -pix_fmt uyvy422 8m.yuv

nv12 to jpeg

ffmpeg -framerate 1 -f rawvideo -pix_fmt nv12 -video_size 1920x1080 -i sample_001.yuv sample_001.jpeg

dump video information

ffmpeg -i sample_h265.mkv -hide_banner

convert h265 frame to nv12

ffmpeg -i sample_h265.mkv -pix_fmt nv12 sample.yuv

strace tools

binary needs full path

/usr/bin/strace /mnt/c/work/github/make_dataset/build/make_offline_data_bin

gdb tools

start debug

/usr/bin/gdb /mnt/c/work/github/make_dataset/build/make_offline_data_bin

set breakpoint at line make_offline_data.cc:8

b make_offline_data.cc:8

run program

r

print variable

p argc