ff_cbs_delete_unit never fails if the index of the unit to delete is
valid, as it is with all current callers of the function. So just assert
in ff_cbs_delete_unit that the index is valid and change the return
value to void in order to remove the callers' checks for whether
ff_cbs_delete_unit failed.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Up until now, ff_cbs_write_packet always initialized the packet
structure it received without documenting this behaviour; furthermore,
the packet's buffer would (on success) be overwritten with the new
buffer without unreferencing the old. This meant that the input packet
had to be either clean (otherwise there would be memleaks) in which case
the initialization is redundant or uninitialized. ff_cbs_write_packet
was never used with uninitialized packets, so the initialization was
redundant. Worse yet, it forced callers to use more than one packet and
made it difficult to add side-data to a packet designated for output,
because said side-data could only be attached after the call to
ff_cbs_write_packet.
This has been changed. It is now allowed to use a non-blank packet.
The currently existing buffer will be unreferenced and replaced by
the new one, as will be the accompanying fields (i.e. data and size).
The rest isn't touched at all.
This change will enable us to use only one packet in the bitstream
filters that rely on CBS.
This commit also updates the documentation of ff_cbs_write_extradata
and ff_cbs_write_packet (to better describe existing behaviour and in
the latter case to also describe the new behaviour).
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Currently, a fragment's unit array is constantly reallocated during
splitting of a packet. This commit changes this: One can keep the units
array by distinguishing between the number of allocated and the number
of valid units in the units array.
The more units a packet is split into, the bigger the benefit.
So MPEG-2 benefits the most; for a video coming from an NTSC-DVD
(usually 32 units per frame) the average cost of cbs_insert_unit (for a
single unit) went down from 6717 decicycles to 450 decicycles (based
upon 10 runs with 4194304 runs each); if each packet consists of only
one unit, it went down from 2425 to 448; for a H.264 video where most
packets contain nine units, it went from 4431 to 450.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@googlemail.com>
* commit 'ce5870a3a8f2b10668ee4f04c2ae0287f66f31b2':
cbs: Refcount all the things!
Some changes for bitstream API.
Merged-by: Mark Thompson <sw@jkqxz.net>
This makes it easier for users of the CBS API to get alloc/free right -
all subelements use the buffer API so that it's clear how to free them.
It also allows eliding some redundant copies: the packet -> fragment copy
disappears after this change if the input packet is refcounted, and more
codec-specific cases are now possible (but not included in this patch).
(cherry picked from commit 867381b8b51fa21fa2b8f071f508f3d39cc9c1f0)
(cherry picked from commit f763489364416bb6866adc4f4a96012dd2ca1bd0)
(cherry picked from commit 067a9ddeb8feff1f724856f0054930c55219f76b)
(cherry picked from commit acf06f45441be24c5cbae0920579cd69427326a1)
(cherry picked from commit 768eb9182e94a94bc2ef46f565a0dac7afef3b57)
(cherry picked from commit e7f64191b27bcf37cbf7006606f0f439c6cdc24f)
