CODEWITHSUNDEEP
ffmpegffprobe
John Doe
John Doe

Reputation: 351

FFmpeg/FFprobe - detect blank/empty/white image

Is it possible, using ffmpeg or ffprobe, to detect if an image is blank? Only containing a single color, e.g. White.

I have done some digging and have come up with nothing at all, I don't even know if this is possible. I intend to execute via a batch file.

Thanks for any pointers.

Upvotes: 0

Views: 1001

Answers (2)

Duke Dougal
Duke Dougal

Reputation: 26406

An implementation in Python based on John Doe's solution.

This counts the number of blank frames in the first 10 seconds of a video.

import json
import shlex
import subprocess


def identify_initial_blank_frames(video_absolute_path):
    # analyse first 10 seconds only
    ffprobe_command = f'''ffprobe -read_intervals %+10  -f lavfi -i "movie={video_absolute_path},signalstats" -show_frames -print_format json'''
    ffprobe_command_single_line = shlex.split(ffprobe_command)
    find_blank_frames_result = subprocess.run(ffprobe_command_single_line, stdout=subprocess.PIPE)
    find_blank_frames_result_json = find_blank_frames_result.stdout.decode('utf-8')
    data = json.loads(find_blank_frames_result_json)

    count = 0
    for index, frame in enumerate(data['frames']):
        # all these color values are the same if the frame is blank
        UMIN = frame['tags']['lavfi.signalstats.UMIN']
        ULOW = frame['tags']['lavfi.signalstats.ULOW']
        UAVG = frame['tags']['lavfi.signalstats.UAVG']
        UHIGH = frame['tags']['lavfi.signalstats.UHIGH']
        UMAX = frame['tags']['lavfi.signalstats.UMAX']
        VMIN = frame['tags']['lavfi.signalstats.VMIN']
        VLOW = frame['tags']['lavfi.signalstats.VLOW']
        VAVG = frame['tags']['lavfi.signalstats.VAVG']
        VHIGH = frame['tags']['lavfi.signalstats.VHIGH']
        VMAX = frame['tags']['lavfi.signalstats.VMAX']
        if UMIN == ULOW == UAVG == UHIGH == UMAX == VMIN == VLOW == VAVG == VHIGH == VMAX:
            print(index)
            count += 1
        else:
            # we have come to the end of the initial contiguous sequence of frames
            break
    print(f'found {count} contiguous blank frames at start of video')

Upvotes: 0

John Doe
John Doe

Reputation: 351

for /f "tokens=* USEBACKQ" %%f in (`ffprobe -f lavfi -i "movie=test.png,signalstats" -show_frames`) do (
set /a line=!line!+1
if !line! EQU 33 set ave=%%f
)

if "!ave:~27,3!"=="235" echo WHITE

Upvotes: 1

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