Full-Range to TV-Level Video "Legalizer"

[chris319]

This is giving me good results converting full-range (8-bit 0 - 255) video to "limited" (8-bit 16 - 235) video.

Note the use of ffv1 version 3 codec.

ffmpeg -y -hide_banner -i "C0042.mp4" -vf scale=w=1280:h=720,lutyuv=y='clip(val,16,235)',lutyuv=u='clip(val,16,240)',lutyuv=v='clip(val,16,240)',setparams=range="tv" -codec:v ffv1 -level 3 -pix_fmt:v yuv422p -color_range "tv" -vb 50M -color_primaries bt709 -color_trc bt709 -colorspace bt709 -c:a pcm_s16be clipped.mov

[chris319]

1080i version:

ffmpeg -y -hide_banner -i "C0015.mp4" -vf tinterlace=4:vlpf,scale=w=1920:h=1080,lutyuv=y='clip(val,20,223)',lutyuv=u='clip(val,16,240)',lutyuv=v='clip(val,16,240)',setparams=range="tv" -codec:v ffv1 -level 3 -pix_fmt:v yuv422p -color_range "tv" -vb 50M -color_primaries bt709 -color_trc bt709 -colorspace bt709  -flags +ilme+ildct  -movflags +write_colr  -c:a pcm_s16be clipped.mov

[jagabo]

You're not converting full range to limited range. You're clamping full range to limited range, losing dark and bright details.

[poisondeathray]

That 1st command will work ok if the input video is flagged full range and it's read as full range. The clipping will occur after the full to limited scaling which occurs automatically if flagged full .

The default behaviour of swscale if it encounters a full range flag is to scale to limited range. In other words, the hidden commands are

in_range=full:out_range=limited

The lutyuv will hard clip values after the scale (resampling can create aliasing and out of range values) . If a video is not flagged full range, but is full range, you need to explicitly input the range parameters. It's good practice to enter them anyways .

-vb 50M will do nothing with ffv1 is the video codec ; ffv1 will always use the bitrate required to achieve losslessness


Why is the 1080i version different for lutyuv ? lutyuv=y='clip(val,20,223)' , not 16-235 ?

[jagabo]

If a video is not flagged full range, but is full range, you need to explicitly input the range parameters.

Ah, that's the problem I was having. The source I converted with the ffmpeg command line was not flagged as full range, but had a full range test pattern.

[chris319]

I discovered a flaw in the program I was using to check video levels. It has now been fixed.

Bandwidth command removed. Changed video range. The input files are flagged as "limited". I have no control over that. The range of values is actually 0 - 255 despite being flagged as "limited". Using limiter instead of clipper.

How's this?

ffmpeg -y -hide_banner -i "C0015.mp4" -vf scale=w=1280:h=720,setparams=range="tv",limiter=16:235:1,limiter=16:240:6  -codec:v ffv1 -level 3 -pix_fmt:v yuv422p -color_range "tv" -color_primaries bt709 -color_trc bt709 -colorspace bt709  -movflags +write_colr  -c:a pcm_s16be limited.mov