relocate_written_data is called in the following situation:
* track headers need to be re-written
* at least one frame has been written already
* the space left right after the track headers does not suffice to
expand the track headers
In such a case all frames that have been written already will be
moved.
However, in certain split modes then current file may actually be a
null I/O, meaning that the current output is discarded. A null I/O
object doesn't return anything when reading for it, causing an endless
loop in the relocation code which calls `read` as often as needed
until everything's been read — which can never happen with a null I/O
object.
However, it makes no sense to try to actually read the data in such a
case, as it will be discarded anyway. Therefore just avoid trying to
read the data in the first place.
Fixes#1944.
Using only a single one may lead to false positives and consequently
to wrong track parameters, especially if the file was cut at an
arbitrary position.
Fixes the audio-related part of #1938.
The old calculation method assumed that all picture set arrays are
always present in the HEVCC. This is not the case: arrays without
picture sets should not be written. Therefore their fixed size
overhead must not be added to the expected list size.
In order not to have to calculate the size in advance, the code has
been changed to write to an auto-resizing instance of mm_mem_io_c.
This is another fix for the video-related part of #1938.
The number of parameter set arrays is not the sum of the number of
VPS, SPS, PPS and SEI NALUs, but the number of different types. For
example, if there's one VPS, one SPS, two PPS and no SEI NALUs, the
number of parameter set arrays must be three and not four.
Fixes the video-related part of #1938.
