Hi On Thu, Nov 30, 2017 at 10:24 AM, <nerbr...@free.fr> wrote: > Hello all, > > I'm encoding my audio files to opus, with the following command: >> ffmpeg -i test.mp3 -acodec libopus -b:a 64000 -vbr on test.opus > (Debian squeeze, ffmpeg version 3.3.5) > > According to wikipedia, the "opus" container should just be an ogg container > (https://en.wikipedia.org/wiki/Opus_%28audio_format%29). > However, encoding my file with an ogg extension : >> ffmpeg -i test.mp3 -acodec libopus -b:a 64000 -vbr on test.ogg > produces a different file from the previous one (md5 are mismatched). >
I know nothing about these formats really, but using md5 for this kind of comparison is sometimes flawed. With some formats, pieces of metadata like 'encoded date', or perhaps a unique ID can be written. So each time you run the same ffmpeg command, you will get a different whole file MD5 value as a few small bits will indeed be different. I mimicked your command and produced opus and ogg outputs from the same input. Using mediainfo's trace feature, it looks to me like both are pretty much identical, they just have different values for 'stream serial number' and 'page checksum'. It looks to me as though both files are pretty much identical otherwise. Here's the output of both trace reports: https://gist.github.com/kieranjol/45edc4871270ce6110d256590e71e229 I used mediainfo --Details=1 test.ogg mediainfo --Details=1 test.opus to get those outputs. Best, Kieran. _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
