[FFmpeg-devel] [PATCH 01/10] checkasm: Add vc1dsp in-loop deblocking filter tests

[Martin Storsjö]

On Fri, 25 Mar 2022, Ben Avison wrote:

> Note that the benchmarking results for these functions are highly dependent
> upon the input data. Therefore, each function is benchmarked twice,
> corresponding to the best and worst case complexity of the reference C
> implementation. The performance of a real stream decode will fall somewhere
> between these two extremes.
>
> Signed-off-by: Ben Avison <bavison at riscosopen.org>
> ---
> tests/checkasm/Makefile   |  1 +
> tests/checkasm/checkasm.c |  3 ++
> tests/checkasm/checkasm.h |  1 +
> tests/checkasm/vc1dsp.c   | 94 +++++++++++++++++++++++++++++++++++++++
> tests/fate/checkasm.mak   |  1 +
> 5 files changed, 100 insertions(+)
> create mode 100644 tests/checkasm/vc1dsp.c

Actually, this test already paid off - thanks! It caught a real issue with 
the existing x86 loopfilter assembly. The stride parameter is 'int', but 
the assembly uses it as a full register without clearing/sign extending 
the upper half.

Instead of complicating the assembly, the usual remedy is to change the 
parameter to ptrdiff_t, to avoid the issue altogether - I'll send a patch 
for that.

// Martin