[FFmpeg-devel] [PATCH v4 7/9] lavc/libopenh264enc: add profile high option support

[Martin Storsjö]

On Wed, 15 Apr 2020, Linjie Fu wrote:

> Add support for PRO_HIGH/PRO_BASELINE in SVC Encoding extention mode,
> which determined by iEntropyCodingModeFlag in ParamTranscode().
>
> <https://github.com/cisco/openh264/blob/master/codec/encoder/core/inc/param_svc.h#L394>
>
> Signed-off-by: Linjie Fu <linjie.fu at intel.com>
> ---
> libavcodec/libopenh264enc.c | 32 ++++++++++++++++++++++++++------
> 1 file changed, 26 insertions(+), 6 deletions(-)
>
> diff --git a/libavcodec/libopenh264enc.c b/libavcodec/libopenh264enc.c
> index a7c389e..0fe8cf4 100644
> --- a/libavcodec/libopenh264enc.c
> +++ b/libavcodec/libopenh264enc.c
> @@ -42,7 +42,7 @@ typedef struct SVCContext {
>     ISVCEncoder *encoder;
>     int slice_mode;
>     int loopfilter;
> -    char *profile;
> +    int profile;
>     int max_nal_size;
>     int skip_frames;
>     int skipped;
> @@ -73,7 +73,11 @@ static const AVOption options[] = {
> #endif
> #endif
>     { "loopfilter", "enable loop filter", OFFSET(loopfilter), AV_OPT_TYPE_INT, { .i64 = 1 }, 0, 1, VE },
> -    { "profile", "set profile restrictions", OFFSET(profile), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, VE },
> +    { "profile", "Set profile restrictions", OFFSET(profile), AV_OPT_TYPE_INT, { .i64 = FF_PROFILE_UNKNOWN }, FF_PROFILE_UNKNOWN, 0xffff, VE, "profile" },
> +#define PROFILE(name, value)  name, NULL, 0, AV_OPT_TYPE_CONST, { .i64 = value }, 0, 0, VE, "profile"
> +        { PROFILE("constrained_baseline", FF_PROFILE_H264_CONSTRAINED_BASELINE) },
> +        { PROFILE("high",                 FF_PROFILE_H264_HIGH) },
> +#undef PROFILE
>     { "max_nal_size", "set maximum NAL size in bytes", OFFSET(max_nal_size), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, VE },
>     { "allow_skip_frames", "allow skipping frames to hit the target bitrate", OFFSET(skip_frames), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, VE },
>     { "cabac", "Enable cabac", OFFSET(cabac), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, VE },
> @@ -109,12 +113,28 @@ static av_cold int svc_encode_init_profile(AVCodecContext *avctx, SEncParamExt *
> {
>     SVCContext *s = avctx->priv_data;
> 
> -    if (s->profile && !strcmp(s->profile, "main"))
> -        param->iEntropyCodingModeFlag = 1; //< 0:CAVLC  1:CABAC
> -    else if (!s->profile && s->cabac)
> +    if (s->profile == FF_PROFILE_UNKNOWN)
> +        s->profile = s->cabac ? FF_PROFILE_H264_HIGH :
> +                                FF_PROFILE_H264_CONSTRAINED_BASELINE;
> +
> +    switch (s->profile) {
> +    case FF_PROFILE_H264_HIGH:
>         param->iEntropyCodingModeFlag = 1;
> -    else
> +        av_log(avctx, AV_LOG_VERBOSE, "Using CABAC, "
> +               "select EProfileIdc PRO_HIGH in libopenh264.\n");
> +        break;
> +    case FF_PROFILE_H264_CONSTRAINED_BASELINE:
> +    case FF_PROFILE_UNKNOWN:
> +        param->iEntropyCodingModeFlag = 0;
> +        av_log(avctx, AV_LOG_VERBOSE, "Using CAVLC, "
> +               "select EProfileIdc PRO_BASELINE in libopenh264.\n");
> +        break;
> +    default:
>         param->iEntropyCodingModeFlag = 0;
> +        av_log(avctx, AV_LOG_WARNING, "Unsupported profile, "
> +               "select EProfileIdc PRO_BASELINE in libopenh264.\n");
> +        break;
> +    }
>
>     return 0;
> }
> -- 
> 2.7.4

This is fine I guess - apparently it changed in OpenH264 1.8, before that, 
setting iEntropyCodingModeFlag = 1 got main profile, not high.

The commit message feels a bit misleading for what the commit really does 
though. The commit message says "add ... support", which sounds like it 
would be a pure addition, while it is a bit of a rewrite, and actually 
removes support for "-profile main" (even though it might have given 
profile high with current OpenH264 versions).

Maybe this would be clearer:
----
libopenh264enc: Rewrite profile handling

Support the profiles "constrained_baseline" and "high". Previously, the 
encoder wrapper supported the parameter value "main", but with recent 
versions of OpenH264, the produed bitstream signaled the profile high 
anyway.
---

That's at least clear with what the change actually does.

// Martin