[FFmpeg-devel] [PATCH] avcodec/libaom: Support monochrome encoding with libaom >= 2.0.1

[James Almer]

On 12/8/2020 2:04 AM, Philip Langdale wrote:
> Monochrome encoding with libaom was buggy for a long time, but this was
> finally sorted out in libaom 2.0.1 (2.0.0 is almost there but was still
> buggy in realtime mode).
> 
> Surprisingly, we've never had an external library feature flag in
> configure before, but it seems reasonable to add such a category.
> 
> Signed-off-by: Philip Langdale <philipl at overt.org>
> ---
>   Changelog              |  1 +
>   configure              |  8 ++++++++
>   libavcodec/libaomenc.c | 14 ++++++++++++++
>   libavcodec/version.h   |  2 +-
>   4 files changed, 24 insertions(+), 1 deletion(-)
> 
> diff --git a/Changelog b/Changelog
> index 503317dfae..8f5e849f8d 100644
> --- a/Changelog
> +++ b/Changelog
> @@ -51,6 +51,7 @@ version <next>:
>   - asubcut filter
>   - Microsoft Paint (MSP) version 2 decoder
>   - Microsoft Paint (MSP) demuxer
> +- AV1 monochrome encoding support via libaom >= 2.0.1
>   
>   
>   version 4.3:
> diff --git a/configure b/configure
> index 10dd40cab8..6c83895414 100755
> --- a/configure
> +++ b/configure
> @@ -1829,6 +1829,10 @@ EXTERNAL_LIBRARY_LIST="
>       vapoursynth
>   "
>   
> +EXTERNAL_LIBRARY_FEATURES="
> +    libaom2
> +"
> +
>   HWACCEL_AUTODETECT_LIBRARY_LIST="
>       amf
>       audiotoolbox
> @@ -2314,6 +2318,7 @@ HAVE_LIST="
>       $ARCH_FEATURES
>       $BUILTIN_LIST
>       $COMPLEX_FUNCS
> +    $EXTERNAL_LIBRARY_FEATURES
>       $HAVE_LIST_CMDLINE
>       $HAVE_LIST_PUB
>       $HEADERS_LIST
> @@ -6329,6 +6334,9 @@ enabled gnutls            && require_pkg_config gnutls gnutls gnutls/gnutls.h gn
>   enabled jni               && { [ $target_os = "android" ] && check_headers jni.h && enabled pthreads || die "ERROR: jni not found"; }
>   enabled ladspa            && require_headers "ladspa.h dlfcn.h"
>   enabled libaom            && require_pkg_config libaom "aom >= 1.0.0" aom/aom_codec.h aom_codec_version
> +if enabled libaom; then
> +    check_pkg_config libaom2 "aom >= 2.0.1" aom/aom_codec.h aom_codec_version

It should be cleaner to do the version check in libaomenc.c

Look at av1_init_static(), where we check for libaom 2 in order to tag 
the wrapper as experimental if the library is too old. In there you can 
add a check for 2.0.1 (like aom_codec_version() >= 0x20001) and make it 
set codec->pix_fmts to a new list of formats that include the gray ones 
depending on the result.

> +fi
>   enabled libaribb24        && { check_pkg_config libaribb24 "aribb24 > 1.0.3" "aribb24/aribb24.h" arib_instance_new ||
>                                  { enabled gpl && require_pkg_config libaribb24 aribb24 "aribb24/aribb24.h" arib_instance_new; } ||
>                                  die "ERROR: libaribb24 requires version higher than 1.0.3 or --enable-gpl."; }
> diff --git a/libavcodec/libaomenc.c b/libavcodec/libaomenc.c
> index 2b0581b15a..6110472b68 100644
> --- a/libavcodec/libaomenc.c
> +++ b/libavcodec/libaomenc.c
> @@ -338,6 +338,10 @@ static int set_pix_fmt(AVCodecContext *avctx, aom_codec_caps_t codec_caps,
>       const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(avctx->pix_fmt);
>       enccfg->g_bit_depth = enccfg->g_input_bit_depth = desc->comp[0].depth;
>       switch (avctx->pix_fmt) {
> +#if HAVE_LIBAOM2
> +    case AV_PIX_FMT_GRAY8:
> +        enccfg->monochrome = 1;
> +#endif

Add a line like

// Fall-through

Here, to hint the compiler to not warn about a missing break.

>       case AV_PIX_FMT_YUV420P:
>           enccfg->g_profile = FF_PROFILE_AV1_MAIN;
>           *img_fmt = AOM_IMG_FMT_I420;
> @@ -351,6 +355,11 @@ static int set_pix_fmt(AVCodecContext *avctx, aom_codec_caps_t codec_caps,
>           enccfg->g_profile = FF_PROFILE_AV1_HIGH;
>           *img_fmt = AOM_IMG_FMT_I444;
>           return 0;
> +#if HAVE_LIBAOM2
> +    case AV_PIX_FMT_GRAY10:
> +    case AV_PIX_FMT_GRAY12:
> +        enccfg->monochrome = 1;
> +#endif

Ditto.

>       case AV_PIX_FMT_YUV420P10:
>       case AV_PIX_FMT_YUV420P12:
>           if (codec_caps & AOM_CODEC_CAP_HIGHBITDEPTH) {
> @@ -1171,6 +1180,11 @@ static const enum AVPixelFormat av1_pix_fmts_highbd[] = {
>       AV_PIX_FMT_YUV444P12,
>       AV_PIX_FMT_GBRP10,
>       AV_PIX_FMT_GBRP12,
> +#if HAVE_LIBAOM2
> +    AV_PIX_FMT_GRAY8,
> +    AV_PIX_FMT_GRAY10,
> +    AV_PIX_FMT_GRAY12,
> +#endif
>       AV_PIX_FMT_NONE
>   };
>   
> diff --git a/libavcodec/version.h b/libavcodec/version.h
> index 1c10d105f6..5b92afe60a 100644
> --- a/libavcodec/version.h
> +++ b/libavcodec/version.h
> @@ -29,7 +29,7 @@
>   
>   #define LIBAVCODEC_VERSION_MAJOR  58
>   #define LIBAVCODEC_VERSION_MINOR 115
> -#define LIBAVCODEC_VERSION_MICRO 101
> +#define LIBAVCODEC_VERSION_MICRO 102
>   
>   #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
>                                                  LIBAVCODEC_VERSION_MINOR, \
>