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...@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

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