Use new vp09 codec string for WebM by default

Configurable under flag --use_legacy_vp9_codec_string, which defaults
to false as all major browsers and platforms support new style vp09
codec string already.

Closes #406.

Change-Id: I22e917777f9d66db815ff9d55eb47b6d55806269

packager/app/test/testdata/vp9-webm-with-blockgroup/output.mpd

@@ -3,7 +3,7 @@
 <MPD xmlns="urn:mpeg:dash:schema:mpd:2011" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xsi:schemaLocation="urn:mpeg:dash:schema:mpd:2011 DASH-MPD.xsd" xmlns:cenc="urn:mpeg:cenc:2013" profiles="urn:mpeg:dash:profile:isoff-on-demand:2011" minBufferTime="PT2S" type="static" mediaPresentationDuration="PT2.7360000610351562S">
   <Period id="0">
     <AdaptationSet id="0" contentType="video" width="320" height="240" frameRate="1000000/33000" subsegmentAlignment="true" par="4:3">
-      <Representation id="0" bandwidth="196039" codecs="vp9" mimeType="video/webm" sar="1:1">
+      <Representation id="0" bandwidth="196039" codecs="vp09.00.10.08.01.02.02.02.00" mimeType="video/webm" sar="1:1">
         <BaseURL>bear-vp9-blockgroup-video.webm</BaseURL>
         <SegmentBase indexRange="302-320" timescale="1000000">
           <Initialization range="0-301"/>

packager/app/test/testdata/vp9-webm/output.mpd

@@ -12,7 +12,7 @@
       </Representation>
     </AdaptationSet>
     <AdaptationSet id="1" contentType="video" width="320" height="240" frameRate="1000000/34000" subsegmentAlignment="true" par="16:9">
-      <Representation id="1" bandwidth="225727" codecs="vp9" mimeType="video/webm" sar="427:320">
+      <Representation id="1" bandwidth="225727" codecs="vp09.00.10.08.01.02.02.02.00" mimeType="video/webm" sar="427:320">
         <BaseURL>bear-320x240-vp9-opus-video.webm</BaseURL>
         <SegmentBase indexRange="302-350" timescale="1000000" presentationTimeOffset="37000">
           <Initialization range="0-301"/>

packager/app/test/testdata/webm-subsample-encryption/output.mpd

@@ -6,7 +6,7 @@
       <ContentProtection schemeIdUri="urn:uuid:1077efec-c0b2-4d02-ace3-3c1e52e2fb4b" cenc:default_KID="31323334-3536-3738-3930-313233343536">
         <cenc:pssh>AAAANHBzc2gBAAAAEHfv7MCyTQKs4zweUuL7SwAAAAExMjM0NTY3ODkwMTIzNDU2AAAAAA==</cenc:pssh>
       </ContentProtection>
-      <Representation id="0" bandwidth="184009" codecs="vp9" mimeType="video/webm" sar="1:1">
+      <Representation id="0" bandwidth="184009" codecs="vp09.00.10.08.00.02.02.02.00" mimeType="video/webm" sar="1:1">
         <BaseURL>bear-320x180-vp9-altref-video.webm</BaseURL>
         <SegmentBase indexRange="353-371" timescale="1000000">
           <Initialization range="0-352"/>

packager/app/test/testdata/webm-vp9-full-sample-encryption/output.mpd

@@ -6,7 +6,7 @@
       <ContentProtection schemeIdUri="urn:uuid:1077efec-c0b2-4d02-ace3-3c1e52e2fb4b" cenc:default_KID="31323334-3536-3738-3930-313233343536">
         <cenc:pssh>AAAANHBzc2gBAAAAEHfv7MCyTQKs4zweUuL7SwAAAAExMjM0NTY3ODkwMTIzNDU2AAAAAA==</cenc:pssh>
       </ContentProtection>
-      <Representation id="0" bandwidth="184009" codecs="vp9" mimeType="video/webm" sar="1:1">
+      <Representation id="0" bandwidth="184009" codecs="vp09.00.10.08.00.02.02.02.00" mimeType="video/webm" sar="1:1">
         <BaseURL>bear-320x180-vp9-altref-video.webm</BaseURL>
         <SegmentBase indexRange="353-371" timescale="1000000">
           <Initialization range="0-352"/>

packager/mpd/base/mpd_utils.cc

@@ -6,6 +6,7 @@
 
 #include "packager/mpd/base/mpd_utils.h"
 
+#include <gflags/gflags.h>
 #include <libxml/tree.h>
 
 #include "packager/base/base64.h"
@@ -18,6 +19,14 @@
 #include "packager/mpd/base/representation.h"
 #include "packager/mpd/base/xml/scoped_xml_ptr.h"
 
+DEFINE_bool(
+    use_legacy_vp9_codec_string,
+    false,
+    "Use legacy vp9 codec string 'vp9' if set to true; otherwise new style "
+    "vp09.xx.xx.xx... codec string will be used. Default to false as indicated "
+    "in https://github.com/google/shaka-packager/issues/406, all major "
+    "browsers and platforms already support the new 'vp09' codec string.");
+
 namespace shaka {
 namespace {
 
@@ -97,8 +106,10 @@ std::string GetCodecs(const MediaInfo& media_info) {
       // new codec strings.
       if (codec == "vp08")
         return "vp8";
-      if (codec == "vp09")
+      if (FLAGS_use_legacy_vp9_codec_string) {
-        return "vp9";
+        if (codec == "vp09")
+          return "vp9";
+      }
     }
     return media_info.video_info().codec();
   }

packager/mpd/base/representation_unittest.cc

@@ -6,6 +6,7 @@
 
 #include "packager/mpd/base/representation.h"
 
+#include <gflags/gflags.h>
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
 #include <inttypes.h>
@@ -22,6 +23,8 @@ using ::testing::Not;
 using ::testing::Values;
 using ::testing::WithParamInterface;
 
+DECLARE_bool(use_legacy_vp9_codec_string);
+
 namespace shaka {
 namespace {
 
@@ -210,9 +213,29 @@ TEST_F(RepresentationTest, CheckVideoInfoVp8CodecInWebm) {
   EXPECT_THAT(representation->GetXml().get(), AttributeEqual("codecs", "vp8"));
 }
 
-// Check that vp9 codec string will be updated for backward compatibility
-// support in webm.
 TEST_F(RepresentationTest, CheckVideoInfoVp9CodecInWebm) {
+  const char kTestMediaInfoCodecVp9[] =
+      "video_info {\n"
+      "  codec: 'vp09.00.00.08.01.01.00.00'\n"
+      "  width: 1280\n"
+      "  height: 720\n"
+      "  time_scale: 10\n"
+      "  frame_duration: 10\n"
+      "  pixel_width: 1\n"
+      "  pixel_height: 1\n"
+      "}\n"
+      "container_type: 3\n";
+  auto representation =
+      CreateRepresentation(ConvertToMediaInfo(kTestMediaInfoCodecVp9),
+                           kAnyRepresentationId, NoListener());
+  ASSERT_TRUE(representation->Init());
+  EXPECT_THAT(representation->GetXml().get(),
+              AttributeEqual("codecs", "vp09.00.00.08.01.01.00.00"));
+}
+
+TEST_F(RepresentationTest, CheckVideoInfoLegacyVp9CodecInWebm) {
+  FLAGS_use_legacy_vp9_codec_string = true;
+
   const char kTestMediaInfoCodecVp9[] =
       "video_info {\n"
       "  codec: 'vp09.00.00.08.01.01.00.00'\n"