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>
This way, every CodedBitstreamType->split_fragment() function can
safely assume the fragment passed to them will be reference counted,
potentially simplifying code.
Reviewed-by: Mark Thompson <sw@jkqxz.net>
Signed-off-by: James Almer <jamrial@gmail.com>
This saves one malloc + memcpy per packet
The CodedBitstreamFragment buffer is padded to follow the requirements
of AVPacket.
Reviewed-by: jkqxz
Signed-off-by: James Almer <jamrial@gmail.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).
This is harmless and should not be a warning - unknown units are passed
through to the write functions unchanged, and no other code will interact
with them.
(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)
