Implemented parsing of HEVC codec ids

media/base/mime_util_internal.cc

Index: media/base/mime_util_internal.cc
diff --git a/media/base/mime_util_internal.cc b/media/base/mime_util_internal.cc
index 882ccb7ac490426f4ff298669dabdd299f5e8b66..d0f2a8f405d97a254304128564a354a48f9e95a5 100644
--- a/media/base/mime_util_internal.cc
+++ b/media/base/mime_util_internal.cc
@@ -149,42 +149,6 @@ static bool IsValidH264Level(uint8_t level_idc) {
           (level_idc >= 50 && level_idc <= 51));
 }
 
-#if BUILDFLAG(ENABLE_HEVC_DEMUXING)
-// ISO/IEC FDIS 14496-15 standard section E.3 describes the syntax of codec ids
-// reserved for HEVC. According to that spec HEVC codec id must start with
-// either "hev1." or "hvc1.". We don't yet support full parsing of HEVC codec
-// ids, but since no other codec id starts with those string we'll just treat
-// any string starting with "hev1." or "hvc1." as valid HEVC codec ids.
-// crbug.com/482761
-static bool ParseHEVCCodecID(const std::string& codec_id,
-                             MimeUtil::Codec* codec,
-                             bool* is_ambiguous) {
-  if (base::StartsWith(codec_id, "hev1.", base::CompareCase::SENSITIVE) ||
-      base::StartsWith(codec_id, "hvc1.", base::CompareCase::SENSITIVE)) {
-    *codec = MimeUtil::HEVC_MAIN;
-
-    // TODO(servolk): Full HEVC codec id parsing is not implemented yet (see
-    // crbug.com/482761). So treat HEVC codec ids as ambiguous for now.
-    *is_ambiguous = true;
-
-    // TODO(servolk): Most HEVC codec ids are treated as ambiguous (see above),
-    // but we need to recognize at least one valid unambiguous HEVC codec id,
-    // which is added into kMP4VideoCodecsExpression. We need it to be
-    // unambiguous to avoid DCHECK(!is_ambiguous) in InitializeMimeTypeMaps. We
-    // also use these in unit tests (see
-    // content/browser/media/media_canplaytype_browsertest.cc).
-    // Remove this workaround after crbug.com/482761 is fixed.
-    if (codec_id == "hev1.1.6.L93.B0" || codec_id == "hvc1.1.6.L93.B0") {
-      *is_ambiguous = false;
-    }
-
-    return true;
-  }
-
-  return false;
-}
-#endif
-
 MimeUtil::MimeUtil() : allow_proprietary_codecs_(false) {
 #if defined(OS_ANDROID)
   platform_info_.is_unified_media_pipeline_enabled =
@@ -298,7 +262,7 @@ void MimeUtil::AddSupportedMediaFormats() {
   CodecSet mp4_video_codecs;
   mp4_video_codecs.insert(H264);
 #if BUILDFLAG(ENABLE_HEVC_DEMUXING)
-  mp4_video_codecs.insert(HEVC_MAIN);
+  mp4_video_codecs.insert(HEVC);
 #endif  // BUILDFLAG(ENABLE_HEVC_DEMUXING)
   CodecSet mp4_codecs(mp4_audio_codecs);
   mp4_codecs.insert(mp4_video_codecs.begin(), mp4_video_codecs.end());
@@ -517,7 +481,7 @@ bool MimeUtil::IsCodecSupportedOnPlatform(
       DCHECK(!is_encrypted || platform_info.has_platform_decoders);
       return true;
 
-    case HEVC_MAIN:
+    case HEVC:
 #if BUILDFLAG(ENABLE_HEVC_DEMUXING)
       if (platform_info.is_unified_media_pipeline_enabled &&
           !platform_info.has_platform_decoders) {
@@ -575,15 +539,9 @@ bool MimeUtil::StringToCodec(const std::string& codec_id,
 // If |codec_id| is not in |string_to_codec_map_|, then we assume that it is
 // either H.264 or HEVC/H.265 codec ID because currently those are the only
 // ones that are not added to the |string_to_codec_map_| and require parsing.
-
-#if BUILDFLAG(ENABLE_HEVC_DEMUXING)
-  if (ParseHEVCCodecID(codec_id, codec, is_ambiguous)) {
-    return true;
-  }
-#endif
-
   VideoCodecProfile profile = VIDEO_CODEC_PROFILE_UNKNOWN;
   uint8_t level_idc = 0;
+
   if (ParseAVCCodecId(codec_id, &profile, &level_idc)) {
     *codec = MimeUtil::H264;
     switch (profile) {
@@ -611,6 +569,18 @@ bool MimeUtil::StringToCodec(const std::string& codec_id,
     return true;
   }
 
+#if BUILDFLAG(ENABLE_HEVC_DEMUXING)
+  if (ParseHEVCCodecId(codec_id, &profile, &level_idc)) {
+    // TODO(servolk): Set |is_ambiguous| to false for now to make sure
+    // CanPlayType result is 'probably' and not 'maybe', since that's what unit
+    // tests expect. We'll need to add platform level checks to ensure that the

[ddorwin, 2016/04/07 20:29:46]

What tests expect 'probably'? Can't we just update these?
The point is that we should err on the side of underpromising, which is 'maybe'.

[servolk, 2016/04/07 20:44:03]

The MediaCanPlayTypeTest.CodecSupportTest_HEVCVariants test that I've added in
content/browser/media/media_canplaytype_browsertest.cc in this CL (see
cast_shell trybot failure in PS #30). I guess we can update that test to expect
'maybe', but then it would fail on platforms that do actually support HEVC.
Since Chromecast is the only platform that enables HEVC I think it's ok to
overpromise here for the time being, while we are working on better
platform-level checks.

[ddorwin, 2016/04/08 20:43:24]

If there are profiles, level, etc. combinations that will always be supported
when this build flag is enabled, you could report "probably" for those, but
currently this would make requests for 12-bit and whatever else return
"probably". If the results are meaningless, authors will learn to ignore them.

As for the tests, you can change kHevcSupported to "maybe" with a TODO noting
this should be "probably" for some, preferably with a crbug ID.

We are going to need to come up with a new solution for those tests when we add
platform querying anyway.

[servolk, 2016/04/08 22:11:45]

Done.

+    // given combination of HEVC profile and level is actually supported.
+    *is_ambiguous = false;
+    *codec = MimeUtil::HEVC;
+    return true;
+  }
+#endif
+
   DVLOG(4) << __FUNCTION__ << ": Unrecognized codec id " << codec_id;
   return false;
 }
@@ -639,7 +609,7 @@ bool MimeUtil::IsCodecProprietary(Codec codec) const {
     case MPEG2_AAC:
     case MPEG4_AAC:
     case H264:
-    case HEVC_MAIN:
+    case HEVC:
       return true;
 
     case PCM: