Notes:
- The loop is biased toward no unescaped bytes as that should be most common.
- The input byte array is slid rather than the (8 times smaller) bit-mask,
  as RISC-V V does not provide a bit-mask (or bit-wise) slide instruction.
- There are two comparisons with 0 per iteration, for the same reason.
- In case of match, bytes are copied until the first match, and the loop is
  restarted after the escape byte. Vector compression (vcompress.vm) could
  discard all escape bytes but that is slower if escape bytes are rare.

Further optimisations should be possible, e.g.:
- processing 2 bytes fewer per iteration to get rid of a 2 slides,
- taking a short cut if the input vector contains less than 2 zeroes.
But this is a good starting point:

T-Head C908:
vc1dsp.vc1_unescape_buffer_c:      12749.5
vc1dsp.vc1_unescape_buffer_rvv_i32: 6009.0

SpacemiT X60:
vc1dsp.vc1_unescape_buffer_c:      11038.0
vc1dsp.vc1_unescape_buffer_rvv_i32: 2061.0

The loop filters can write before the pointer given to them;
the actual test invocations correctly used an offset, while
the benchmark calls were lacking an offset. Therefore, when
running with benchmarking, these tests could have spurious
failures.
Signed-off-by: Martin Storsjö <martin@martin.st>

Helps make sense of the possible noise in the results.

Some timers on certain device and test combinations can produce noisy
results, affecting the reliability of performance measurements. One
notable example of this is the Canaan K230 RISC-V development board.

An option to adjust the number of samples by an exponent (--runs) has
been added, allowing developers to increase the sample count for more
reliable results.
Signed-off-by: J. Dekker <jdek@itanimul.li>

Don't benchmark every single combination of widths and heights;
only benchmark cases which are squares (like in vvc_mc.c).

Contrary to vvc_mc, which increases sizes by doubling dimensions,
vvc_alf tests all sizes in increments of 4. Limit benchmarking to
the cases which are powers of two.

This reduces the number of benchmarked cases from 3072 down to 18.

see https://dvb.org/specifications/verification-validation/vvc-test-content/

passed clips:
    RPR_A_Alibaba_4.bit
    RPR_B_Alibaba_3.bit
    RPR_C_Alibaba_3.bit
    RPR_D_Qualcomm_1.bit
    VVC_HDR_UHDTV1_OpenGOP_Max3840x2160_50fps_HLG10_res_change_with_RPR.ts

For RPR, the current frame may reference a frame with a different resolution.
Therefore, we need to consider frame scaling when we wait for reference pixels.

a preparation for Reference Picture Resampling

Signed-off-by: Zhao Zhili <zhilizhao@tencent.com>

Matches other hwaccels.

Tested-by: Tong Wu <tong1.wu@intel.com>
Signed-off-by: oltolm <oleg.tolmatcev@gmail.com>

Also use loop scope for iterators while just at it.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

Because of ffio_ensure_seekback() a seek error normally should only happen if
the end of file is reached during checking for the junk run-in. Also use proper
error code.
Signed-off-by: Marton Balint <cus@passwd.hu>

We are protecting the checked buffer with ffio_ensure_seekback(), so if the
inner check fails with a seek error, that likely means the end of file was
reached when checking for the next frame. This could also be the result of a
wrongly guessed (larger than normal) frame size, so let's continue the loop
instead of breaking out early. It will end sooner or later anyway.
Signed-off-by: Marton Balint <cus@passwd.hu>

Otherwise the subsequent ffio_ensure_seekback calls destroy the buffer of the
earlier. The worst case ~66kB seekback is so small it is easier to request it
entirely.

Fixes ticket #10837, a regression since
0d17f522.
Signed-off-by: Marton Balint <cus@passwd.hu>

Signed-off-by: LuMingYin <lumingyindetect@163.com>
Signed-off-by: Zhao Zhili <zhilizhao@tencent.com>

Signed-off-by: LuMingYin <lumingyindetect@163.com>
Signed-off-by: Zhao Zhili <zhilizhao@tencent.com>

Signed-off-by: LuMingYin <lumingyindetect@163.com>
Reviewed-by: Steven Liu <lq@chinaffmpeg.org>
Signed-off-by: Zhao Zhili <zhilizhao@tencent.com>

Reviewed-by: Nuo Mi <nuomi2021@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>

Should fix many Coverity false positives, namely #1457947-#1457994
as well as #1461195-#146210.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

Fixes Coverity issue #1516957.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

Do this by attaching the FilterGraph directly to more permanent
storage from which it will be automatically freed.
Fixes Coverity issue #1596533.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

Fixes Coverity issue #1591795.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>