Adobe Media Encoder produces slightly different files from the same input

[miguelmorin]

I was encoding a video file with Adobe Media Encoder CC 2019 when the computer went to sleep because of a loss of power. Out of curiosity, I restarted the process: I renamed the output file, reset the status of the encoding job, and launched it again. The result is different since it has a different number of bytes:

$ ls -lat ep16_3*
-rw-r--r--@ 1 user  staff  591181005 11 Jan 10:01 ep16_3.mp4
-rw-r--r--@ 1 user  staff  591178262 11 Jan 09:04 ep16_3_interrupted.mp4

I watched both files and do not see a difference. I suspect that the difference comes from compression, whose result may allow for random bits. If it were only that, the files would have the same size in bytes and different bit values. But here, the file size is also different.

Why does this hapen, and how to inspect the difference between the files?

[badyu17]

If the encoder has VBV buffer, the output is not deterministic afaik. What are your settings? Adobe Media Encoder probably uses Main Concept encoding library which uses VBV for constant and variable bitrate modes.

[miguelmorin]

Thanks. My settings were "Match source - High bitrate". Yes, Adobe Media Encoder seems to have Main Concept encoding built-in: http://www.digitalfaq.com/forum/video-editing/7960-adobe-premiere-cs3.html.