ISMV lacks any sort of edit list support, as well as tfxd is
effectively the PTS of the fragment for most intents and purposes.
Thus, if b-frames are requested without negative CTS offsets you
end up with N frames' worth of delay (tfxd PTS plus the CTS offset
of the first sample). Negative CTS offsets enable the first sample
to have CTS=DTS, and thus a/v desync due to b-frame reorder delay
is avoided.
According to the PIFF specification[1] the base_data_offset field MUST be
omitteed. See section 5.2.17. Since the ISMV files created by ffmpeg state
that they are 'piff' compatible via 'ftyp' box, this needs to be corrected.
[1] http://www.iis.net/learn/media/smooth-streaming/protected-interoperable-file-format
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is based on libav's implementation and
makes sure to compare output timestamps together.
It also reduces the differences with avconv.
The changes to the test reference files are caused
by an additional packet at the end, the timestamp
of the frame encoded by this packet is always
strictly below the limit stated by the -t option.
Jan Ekström
Michael Niedermayer
Jeremy Hinegardner
Paul B Mahol
Nicolas George
Reimar Döffinger