Is there any command line application that can tell me if 2 video files are the same?

Question

I downloaded a bunch of photos and movie files from my iPhone into a folder on my PC. Then I redownloaded them to a different folder on my PC. Then I diffed the 2 folders, and some of the photos and movie files have differences. I want to make sure the only differences are in the metadata, and that the photo data and movie data are still the same.

I know I can use the compare command in ImageMagick to determine if any pixels are different between 2 images.

Is there any command line software that can compare 2 video files (specifically .MOV files) and tell me if the video data is exactly the same? This software must run on Windows and preferably be free.

I know that FFmpeg can calculate an MD5 for a video file, but that results in different MD5 values for 2 different copies of the same video file (unedited on my iPhone, but transferred to my PC on different days which somehow resulted in the internal data being different).

Answer 1

ffmpeg is an example of a popular tool that can compare video frames.

It implements multiple algorithms that can do that:

• SSIM (Structural Similarity Metric) - it compares sources and results in a value between 0 and 1. Sources need to have the same number of frames, resolution and pixel format for the result to be accurate
• PSNR (Peak Signal to Noise Ratio) - compares sources and measures difference in dB. Same requirements as above.

Example command from the docs that uses both SSIM and PSNR:

ffmpeg -i input.mp4 -i input2.mp4 -lavfi "ssim;[0:v][1:v]psnr" -f null -

You can parse the output of that, which looks like this for the same video:

[Parsed_ssim_0 @ 000002c88edeedc0] SSIM R:1.000000 (inf) G:1.000000 (inf) B:1.000000 (inf) All:1.000000 (inf)
[Parsed_psnr_1 @ 000002c88edeeec0] PSNR r:inf g:inf b:inf average:inf min:inf max:inf

and extract inf if the videos are the same.

There's also VMAF (Video Multi-Method Assessment Fusion) as a more robust tool with additional options, but that ma be not included in some builds.