Up until now, a temporary variable was used and initialized every time a
value was read in CBS; if reading turned out to be successfull, this
value was overwritten (without having ever been looked at) with the
value read if reading was successfull; on failure the variable wasn't
touched either. Therefore these initializations can be and have been
removed.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
cbs_h2645_read_more_rbsp_data does not handle malformed input very well:
1. If there were <= 8 bits left in the bitreader, these bits were read
via show_bits. But show_bits requires the number of bits to be read to
be > 0 (internally it shifts by 32 - number of bits to be read which is
undefined behaviour if said number is zero; there is also an assert for
this, but it is only an av_assert2). Furthermore, in this case a shift
by -1 was performed which is of course undefined behaviour, too.
2. If there were > 0 and <= 8 bits left and all of them were zero
(this can only happen for defective input), it was reported that there
was further RBSP data.
This can lead to an infinite loop in H.265's cbs_h265_read_extension_data
corresponding to the [vsp]ps_extension_data_flag syntax elements. If the
relevant flag indicates the (potential) occurence of these syntax elements,
while all bits after this flag are zero, cbs_h2645_read_more_rbsp_data
always returns 1 on x86. Given that a checked bitstream reader is used,
we are also not "saved" by an overflow in the bitstream reader's index.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Given the recent changes to ff_cbs_delete_unit, it is no longer sensible
to use a return value for ff_cbs_h264_delete_sei_message; instead, use
asserts to ensure that the required conditions are met and remove the
callers' checks for the return value. Also, document said conditions.
An assert that is essentially equivalent to the one used in
ff_cbs_delete_unit has been removed, too.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
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>
Now memcpy can be avoided for NAL units containing escapes, too.
Particularly improves performance for files with hardcoded black bars.
For such a file, time spent in cbs_h2645_split_fragment went down from
369410 decicycles to 327677 decicycles. (It were 379114 decicycles when
every NAL unit was copied.)
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@googlemail.com>
This is in preparation for a patch for cbs_h2645. Now the packet's
rbsp_buffer can be owned by an AVBuffer.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@googlemail.com>
Now memcpy is avoided for NAL units that don't contain 0x03 escape
characters.
Improves performance of cbs_h2645_fragment_add_nals from 36940
decicycles to 6364 decicycles based on 8 runs with a 5.1 Mb/s H.264
sample (262144 runs each).
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@googlemail.com>
Signed-off-by: Mark Thompson <sw@jkqxz.net>
Supports both prefix and suffix SEI, decoding all of the common SEI
types and some more obscure ones. Most of this is tested by the
existing tests in fate.
Instead of using a combination of bitreader and -writer for copying data,
one can byte-align the (obsolete and removed) bitreader to improve performance.
With the right alignment one can even use memcpy. The right alignment
normally exists for CABAC and hence for H.265 in general.
For aligned data this reduced the time to copy the slicedata from
776520 decicycles to 33889 with 262144 runs and a 6.5mb/s H.264 video.
For unaligned data the number went down from 279196 to 97739 decicycles.
Signed-off-by: Mark Thompson <sw@jkqxz.net>
64c50c0e97 declared support for decomposing
them but omitted to implement it; this adds an implementation.
Also do the same for end-of-stream NAL units, since they are equivalent.
Similar to H264, cbs_h265_{read, write}_nal_unit() can handle HEVC
prefix SEI NAL units. Currently mastering display colour volume SEI
message is added only, we may add more SEI message if needed later
Signed-off-by: Haihao Xiang <haihao.xiang@intel.com>
Removes unnecessary data copies, and partially fixes potential issues
with dangling references held in said lists.
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 'eccc03c8fbc603a0a3257df66f0705f74fe2581a':
cbs_h264: Add support for filler NAL units
Some bitstream -> get_bits.
Merged-by: Mark Thompson <sw@jkqxz.net>
* commit 'a2ca8ed903b435446031a8a0792ca535e6ee2913':
cbs_h264: Add utility functions to insert/delete SEI messages
Merged-by: Mark Thompson <sw@jkqxz.net>
* commit 'ce5870a3a8f2b10668ee4f04c2ae0287f66f31b2':
cbs: Refcount all the things!
Some changes for bitstream API.
Merged-by: Mark Thompson <sw@jkqxz.net>
* commit '0e4c166cdd6446522a085dd9731967d09ac71f72':
cbs_h2645: Remove active ps references when it is replaced
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).
