Hello (again) guys!
Sorry to bother, but I just can't get this one off my mind.

Check this out. I rtmpdump:ed some [totally legit] streams from the world wide überspace. They landed as .mp4 locally. MediaInfo tells me that the container itself is "Flash" and that they contain one AVC video stream and one AAC audio stream. So far so good. Now, I would rather like a traditional ISOM/MP4 container, so I did a simple 'mp4box -add stream.mp4 stream-fixed.mp4', which obviously wouldn't cut it. It said unknown media. I assume mp4box doesn't support Flash container for input.

Anyway, I found a solution in the [wonderful] all-around utility ffmpeg. Simply 'ffmpeg -i stream.mp4 -acodec copy -vcodec copy stream-fixed.mp4' did the trick. But here comes the strange part. When I pulled MediaInfo on this new .mp4 file, I notice "Duration_LastFrame: -20ms". What does that mean? I did some Google searching but came up empty-handed, without explanation, only a couple of random occurrences in a couple of MediaInfo dumps (where that line wasn't the headline).

Anyways, I actually prefer Matroska over all other media containers. So a "mkvmerge -o stream-fixed.mkv stream-fixed.mp4" was my final mux. Now, that weird "Duration_LastFrame: -20ms" line was omitted from the MediaInfo dump. Strange, huh? Did it have any significance at all? Just curious.

Ty in adv~
Regards~