Bug 1262659 - Report HTTP Live Streaming playback requests. r=cpearce,bsmedberg

Identify HLS media types (and related m3u playlists) and report
telemetry about how often we fail to play them. This is designed
to measure popularity to inform decisions about support for this
format.

MozReview-Commit-ID: Fp8lNMOJKyA

dom/media/DecoderTraits.cpp

@@ -9,6 +9,7 @@
 #include "nsCharSeparatedTokenizer.h"
 #include "nsMimeTypes.h"
 #include "mozilla/Preferences.h"
+#include "mozilla/Telemetry.h"
 
 #include "OggDecoder.h"
 #include "OggReader.h"
@@ -172,6 +173,21 @@ DecoderTraits::IsWebMAudioType(const nsACString& aType)
   return aType.EqualsASCII("audio/webm");
 }
 
+static char const *const gHttpLiveStreamingTypes[] = {
+  // For m3u8.
+  // https://tools.ietf.org/html/draft-pantos-http-live-streaming-19#section-10
+  "application/vnd.apple.mpegurl",
+  // Some sites serve these as the informal m3u type.
+  "audio/x-mpegurl",
+  nullptr
+};
+
+static bool
+IsHttpLiveStreamingType(const nsACString& aType)
+{
+  return CodecListContains(gHttpLiveStreamingTypes, aType);
+}
+
 #ifdef MOZ_OMX_DECODER
 static const char* const gOmxTypes[] = {
   "audio/mpeg",
@@ -477,6 +493,10 @@ DecoderTraits::CanHandleMediaType(const char* aMIMEType,
 {
   MOZ_ASSERT(NS_IsMainThread());
 
+  if (IsHttpLiveStreamingType(nsDependentCString(aMIMEType))) {
+    Telemetry::Accumulate(Telemetry::MEDIA_HLS_CANPLAY_REQUESTED, true);
+  }
+
   if (aHaveRequestedCodecs) {
     CanPlayStatus result = CanHandleCodecsType(aMIMEType,
                                                aRequestedCodecs,
@@ -621,6 +641,11 @@ InstantiateDecoder(const nsACString& aType,
   }
 #endif
 
+  if (IsHttpLiveStreamingType(aType)) {
+    // We don't have an HLS decoder.
+    Telemetry::Accumulate(Telemetry::MEDIA_HLS_DECODER_SUCCESS, false);
+  }
+
   return nullptr;
 }
 

toolkit/components/telemetry/Histograms.json

@@ -6263,6 +6263,21 @@
     "description": "Whether Ogg audio/video encountered are chained or not.",
     "bug_numbers": [1230295]
   },
+  "MEDIA_HLS_CANPLAY_REQUESTED": {
+    "alert_emails": ["ajones@mozilla.com", "giles@mozilla.com"],
+    "expires_in_version": "50",
+    "kind": "boolean",
+    "description": "Reports a true value when a page requests canPlayType for an HTTP Live Streaming media type (or generic m3u playlist).",
+    "bug_numbers": [1262659]
+  },
+  "MEDIA_HLS_DECODER_SUCCESS": {
+    "alert_emails": ["ajones@mozilla.com", "giles@mozilla.com"],
+    "expires_in_version": "50",
+    "kind": "boolean",
+    "description": "Reports whether a decoder for an HTTP Live Streaming media type was created when requested.",
+    "bug_numbers": [1262659]
+
+  },
   "VIDEO_MFT_OUTPUT_NULL_SAMPLES": {
     "alert_emails": ["cpearce@mozilla.com"],
     "expires_in_version": "53",