> On Jan 13, 2016, at 14:17, Robert Krüger <[email protected]> wrote: > > On Wed, Jan 13, 2016 at 12:53 PM, Christoph Gerstbauer < > [email protected]> wrote: > >> FFmpeg allows me to set a timecode of 24:00:00:00 and beyond. >> >> e.g "-timecode 24:00:00:00" >> >> When I make an MXF D10 for example, the value of 24:00:00:00 is still in >> the file. >> Most but not all programs ignore this and display 00:00:00:00 correctly. >> >> Here are some sample extractions of the timecode offset value in different >> mxf d10 files generated by ffmpeg: >> >> PAL 25fps: >> >> -timecode 12:34:56:11 -> in file: 11477b hex -> 1132411 dec >> >> -timecode 10:00:00:00 -> in file: 0dbba0 hex -> 900000 dec >> >> -timecode 20:00:00:00 -> in file: 1b7740 hex -> 1800000 dec >> >> -timecode 23:59:59:24 -> in file: 20f57f hex -> 2159999 dec >> >> -timecode 24:00:00:00 -> in file: 20f580 hex -> 2160000 dec -> 24h >> >> -timecode 24:00:00:01 -> in file: 20f581 hex -> 2160001 dec >> >> -timecode 25:00:00:00 -> in file: 225510 hex -> 2250000 dec -> 25h >> >> >> NTSC 30fps >> >> -timecode 23:59:59;29 -> in file: 2782df hex -> 2589407 dec >> >> -timecode 24:00:00;00 -> in file: 2782e0 hex -> 2589408 dec >> >> >> Why is this possible to set a timecode after 23:59:59:XX? >> Is there a usecase? >> > > I wasn't able to find any official spec that says what the limit for the > hour part is but since it in the general case does not define a time of day > but an offset, why limit it to 25 hours and not use the full 100? On a > side-note, I have not come across a real-world use case for a timecode of > that magnitude either. > Some forms of TC just lack the space to store higher numbers IIRC (LTC / VITC, perhaps also in MpegII frame headers) But there is logic in not going higher, as it is ‘time’. For a real world use case, in the old days of tape, a reelname most of the time corresponded with the hour. So a production with more than 24 tapes needed better administration in reel names that had to be written on the tape and box.
Bouke _______________________________________________ ffmpeg-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/ffmpeg-user
