[FFmpeg-devel] [PATCH] avcodec/exr: preserve half-float NaN bits and add fate test

[Mark Reid]

On Sun, Nov 22, 2020 at 8:32 PM <mindmark at gmail.com> wrote:

> From: Mark Reid <mindmark at gmail.com>
>
> Hi,
> This patch handles NaNs more like the offical implentation handles them,
> preserving
> the original bits.
>
>
> https://github.com/AcademySoftwareFoundation/openexr/blob/RB-2.5/IlmBase/Half/toFloat.cpp#L111
>
> It also adds a fate test that is a 256x256 exr containing all possible
> 16bit half-float values.
>
> Here is a link to download the fate test file, if someone could add it to
> fate me
>
> https://www.dropbox.com/s/2q4jg8w489aunsf/rgb_scanline_zip_half_float_0x0_to_0xFFFF.exr
>
> ---
>  libavcodec/exr.c                                    | 3 +--
>  tests/fate/image.mak                                | 2 ++
>  tests/ref/fate/exr-rgb-scanline-zip-half-0x0-0xFFFF | 6 ++++++
>  3 files changed, 9 insertions(+), 2 deletions(-)
>  create mode 100644 tests/ref/fate/exr-rgb-scanline-zip-half-0x0-0xFFFF
>
> diff --git a/libavcodec/exr.c b/libavcodec/exr.c
> index d233dd43fb..6e6ce4275c 100644
> --- a/libavcodec/exr.c
> +++ b/libavcodec/exr.c
> @@ -193,8 +193,7 @@ static union av_intfloat32 exr_half2float(uint16_t hf)
>          // half-float NaNs will be converted to a single precision NaN
>          // half-float Infs will be converted to a single precision Inf
>          exp = FLOAT_MAX_BIASED_EXP;
> -        if (mantissa)
> -            mantissa = (1 << 23) - 1;    // set all bits to indicate a NaN
> +        mantissa <<= 13; // preserve half-float NaN bits if set
>      } else if (exp == 0x0) {
>          // convert half-float zero/denorm to single precision value
>          if (mantissa) {
> diff --git a/tests/fate/image.mak b/tests/fate/image.mak
> index 22072a62f1..c453f0f79c 100644
> --- a/tests/fate/image.mak
> +++ b/tests/fate/image.mak
> @@ -317,6 +317,8 @@ fate-exr-rgb-scanline-half-zip-dw-outside: CMD =
> framecrc -i $(TARGET_SAMPLES)/e
>  FATE_EXR += fate-exr-rgb-tile-half-zip-dw-outside
>  fate-exr-rgb-tile-half-zip-dw-outside: CMD = framecrc -i
> $(TARGET_SAMPLES)/exr/rgb_tile_half_zip_dw_outside.exr -pix_fmt gbrpf32le
>
> +FATE_EXR += fate-exr-rgb-scanline-zip-half-0x0-0xFFFF
> +fate-exr-rgb-scanline-zip-half-0x0-0xFFFF: CMD = framecrc -i
> $(TARGET_SAMPLES)/exr/rgb_scanline_zip_half_float_0x0_to_0xFFFF.exr
> -pix_fmt gbrpf32le
>
>  FATE_EXR-$(call DEMDEC, IMAGE2, EXR) += $(FATE_EXR)
>
> diff --git a/tests/ref/fate/exr-rgb-scanline-zip-half-0x0-0xFFFF
> b/tests/ref/fate/exr-rgb-scanline-zip-half-0x0-0xFFFF
> new file mode 100644
> index 0000000000..b6201116fe
> --- /dev/null
> +++ b/tests/ref/fate/exr-rgb-scanline-zip-half-0x0-0xFFFF
> @@ -0,0 +1,6 @@
> +#tb 0: 1/25
> +#media_type 0: video
> +#codec_id 0: rawvideo
> +#dimensions 0: 256x256
> +#sar 0: 1/1
> +0,          0,          0,        1,   786432, 0x1445e411
> --
> 2.29.2
>
>
ping