[FFmpeg-devel] [PATCH] Add support for the new key & value API in libaom.

[Andreas Rheinhardt]

Bohan Li:
> This key & value API can greatly help with users who wants to try
> libaom-av1 specific options that are not supported by ffmpeg options.
> 
> As was previously discussed in this thread:
> https://lists.ffmpeg.org/pipermail/ffmpeg-devel/2020-October/271658.
> 
> The commit that added the API to libaom:
> https://aomedia.googlesource.com/aom/+/c1d42fe6615c96fc929257
> 
> The libaom issue tracker:
> https://bugs.chromium.org/p/aomedia/issues/detail?id=2875
> 
> Signed-off-by: Bohan Li <bohanli at google.com>
> ---
>  doc/encoders.texi      | 10 ++++++++++
>  libavcodec/libaomenc.c | 32 ++++++++++++++++++++++++++++++++
>  2 files changed, 42 insertions(+)
> 
> diff --git a/doc/encoders.texi b/doc/encoders.texi
> index c2ba7d3e6f..3f32303b3d 100644
> --- a/doc/encoders.texi
> +++ b/doc/encoders.texi
> @@ -1684,6 +1684,16 @@ Enable interintra compound. Default is true.
>  @item enable-smooth-interintra (@emph{boolean}) (Requires libaom >= v2.0.0)
>  Enable smooth interintra mode. Default is true.
>  
> + at item libaom-params
> +Set libaom options using a list of @var{key}=@var{value} pairs separated
> +by ":". See @command{aomenc --help} for a list of options.
> +
> +For example to specify libaom encoding options with @option{-libaom-params}:
> +
> + at example
> +ffmpeg -i input -c:v libaom-av1 -b:v 500K -libaom-params tune=psnr:enable-tpl-model=1 output.mp4
> + at end example
> +
>  @end table
>  
>  @section libsvtav1
> diff --git a/libavcodec/libaomenc.c b/libavcodec/libaomenc.c
> index 342d0883e4..b7c5a64417 100644
> --- a/libavcodec/libaomenc.c
> +++ b/libavcodec/libaomenc.c
> @@ -124,6 +124,7 @@ typedef struct AOMEncoderContext {
>      int enable_diff_wtd_comp;
>      int enable_dist_wtd_comp;
>      int enable_dual_filter;
> +    AVDictionary *extra_params;
>  } AOMContext;
>  
>  static const char *const ctlidstr[] = {
> @@ -318,6 +319,27 @@ static av_cold int codecctl_int(AVCodecContext *avctx,
>      return 0;
>  }
>  
> +static av_cold int codec_set_option(AVCodecContext *avctx,
> +                                    const char* key,
> +                                    const char* value)
> +{
> +    AOMContext *ctx = avctx->priv_data;
> +    char buf[80];
> +    int width = -30;
> +    int res;
> +
> +    snprintf(buf, sizeof(buf), "%s:", key);
> +    av_log(avctx, AV_LOG_DEBUG, "  %*s%s: %s\n", width, buf, key, value);

This will print key twice (unless your key is so long that it doesn't
fit into buf anymore). Actually, I do not get why you use buf at all.

> +
> +    res = aom_codec_set_option(&ctx->encoder, key, value);
> +    if (res != AOM_CODEC_OK) {
> +        log_encoder_error(avctx, buf);

Unless key is oversized, your string will already end with a ':' and the
message from log_encoder_error will contain a "::". So this is one more
reason to get rid of buf.

> +        return AVERROR(EINVAL);
> +    }
> +
> +    return 0;
> +}
> +
>  static av_cold int aom_free(AVCodecContext *avctx)
>  {
>      AOMContext *ctx = avctx->priv_data;
> @@ -874,6 +896,15 @@ static av_cold int aom_init(AVCodecContext *avctx,
>          codecctl_int(avctx, AV1E_SET_ENABLE_INTRABC, ctx->enable_intrabc);
>  #endif
>  
> +#if AOM_ENCODER_ABI_VERSION >= 23
> +    {
> +      AVDictionaryEntry *en = NULL;
> +      while ((en = av_dict_get(ctx->extra_params, "", en, AV_DICT_IGNORE_SUFFIX))) {
> +        codec_set_option(avctx, en->key, en->value);
> +      }
> +    }
> +#endif
> +
>      // provide dummy value to initialize wrapper, values will be updated each _encode()
>      aom_img_wrap(&ctx->rawimg, img_fmt, avctx->width, avctx->height, 1,
>                   (unsigned char*)1);
> @@ -1299,6 +1330,7 @@ static const AVOption options[] = {
>      { "enable-masked-comp",           "Enable masked compound",                            OFFSET(enable_masked_comp),           AV_OPT_TYPE_BOOL, {.i64 = -1}, -1, 1, VE},
>      { "enable-interintra-comp",       "Enable interintra compound",                        OFFSET(enable_interintra_comp),       AV_OPT_TYPE_BOOL, {.i64 = -1}, -1, 1, VE},
>      { "enable-smooth-interintra",     "Enable smooth interintra mode",                     OFFSET(enable_smooth_interintra),     AV_OPT_TYPE_BOOL, {.i64 = -1}, -1, 1, VE},
> +    { "libaom-params",                "Extra parameters for libaom",                       OFFSET(extra_params),                 AV_OPT_TYPE_DICT, { 0 },        0, 0, VE },
>      { NULL },
>  };
>  
>