Fix: Adding list of supported codecs for MP4 containers

net/base/mime_util.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <algorithm>
 #include <iterator>
 #include <map>
 #include <string>
 
 #include "base/containers/hash_tables.h"
@@ skipping 60 matching lines @@
 
   bool IsMimeType(const std::string& type_string) const;
 
   bool AreSupportedMediaCodecs(const std::vector<std::string>& codecs) const;
 
   void ParseCodecString(const std::string& codecs,
                         std::vector<std::string>* codecs_out,
                         bool strip);
 
   bool IsStrictMediaMimeType(const std::string& mime_type) const;
-  bool IsSupportedStrictMediaMimeType(
+  CanPlayType IsSupportedStrictMediaMimeType(
       const std::string& mime_type,
       const std::vector<std::string>& codecs) const;
 
   void RemoveProprietaryMediaTypesAndCodecsForTests();
 
  private:
   friend struct base::DefaultLazyInstanceTraits<MimeUtil>;
 
   typedef base::hash_set<std::string> MimeMappings;
   typedef std::map<std::string, MimeMappings> StrictMappings;
 
+  typedef std::vector<std::string> MimeExpressionMappings;
+  typedef std::map<std::string, MimeExpressionMappings>
+      StrictExpressionMappings;
+
   MimeUtil();
 
   // Returns true if |codecs| is nonempty and all the items in it are present in
   // |supported_codecs|.
   static bool AreSupportedCodecs(const MimeMappings& supported_codecs,
                                  const std::vector<std::string>& codecs);
+  static bool AreSupportedCodecsWithProfile(
+      const MimeExpressionMappings& supported_codecs,
+      const std::vector<std::string>& codecs);
 
   // For faster lookup, keep hash sets.
   void InitializeMimeTypeMaps();
 
   bool GetMimeTypeFromExtensionHelper(const base::FilePath::StringType& ext,
                                       bool include_platform_types,
                                       std::string* mime_type) const;
 
   MimeMappings image_map_;
   MimeMappings media_map_;
   MimeMappings non_image_map_;
   MimeMappings unsupported_text_map_;
   MimeMappings javascript_map_;
   MimeMappings codecs_map_;
 
   StrictMappings strict_format_map_;
+  StrictExpressionMappings strict_mp4_format_map_;
 };  // class MimeUtil
 
 // This variable is Leaky because we need to access it from WorkerPool threads.
 static base::LazyInstance<MimeUtil>::Leaky g_mime_util =
     LAZY_INSTANCE_INITIALIZER;
 
 struct MimeInfo {
   const char* mime_type;
   const char* extensions;  // comma separated list
 };
@@ skipping 328 matching lines @@
   { "audio/wav", "1" },
   { "audio/x-wav", "1" },
   { "video/ogg", "opus,theora,vorbis" },
   { "audio/ogg", "opus,vorbis" },
   { "application/ogg", "opus,theora,vorbis" },
   { "audio/mpeg", "" },
   { "audio/mp3", "" },
   { "audio/x-mp3", "" }
 };
 
+static const char* kProprietaryAudioCodecsExpression =
+    "mp4a,mp4a.40,mp4a.67,mp4a.40.?,mp4a.67.?";

[amogh.bihani, 2014/05/16 11:25:29]

acolwell@
I think we should keep mp4a in our list, removing it might as well break some
websites.

+static const char* kProprietaryCodecsExpression =
+    "avc1,avc3,avc1.??????,avc3.??????,"
+    "mp4a,mp4a.40,mp4a.67,mp4a.40.?,mp4a.67.?";
+
+static const MediaFormatStrict format_mp4_codec_mappings[] = {
+  { "audio/mp4", kProprietaryAudioCodecsExpression },
+  { "audio/x-m4a", kProprietaryAudioCodecsExpression },
+  { "video/mp4", kProprietaryCodecsExpression },
+  { "video/x-m4v", kProprietaryCodecsExpression },
+  { "application/x-mpegurl", kProprietaryCodecsExpression },
+  { "application/vnd.apple.mpegurl", kProprietaryCodecsExpression }
+};
+
 MimeUtil::MimeUtil() {
   InitializeMimeTypeMaps();
 }
 
 // static
 bool MimeUtil::AreSupportedCodecs(const MimeMappings& supported_codecs,
                                   const std::vector<std::string>& codecs) {
   if (supported_codecs.empty())
     return codecs.empty();
 
   for (size_t i = 0; i < codecs.size(); ++i) {
     if (supported_codecs.find(codecs[i]) == supported_codecs.end())
       return false;
   }
   return !codecs.empty();
 }
 
+bool MimeUtil::AreSupportedCodecsWithProfile(
+    const MimeExpressionMappings& supported_codecs,
+    const std::vector<std::string>& codecs) {
+  for (size_t i = 0; i < codecs.size(); ++i) {

[ddorwin, 2014/05/16 18:49:49]

If the above function checks supported_codecs.empty() first, this one should too
for consistency.

[AmoghBihani, 2014/05/16 19:18:01]

This method is called only for MP4 and HLS containers. Supported codecs will
never be empty(line 471-484. Adding this check might introduce dead code.

The supported_codecs.empty() check was added for mp3 containers which do not
take any codec parameter.
You can view the change in
https://codereview.chromium.org/228823003/diff/100001/net/base/mime_util.cc?c...

[ddorwin, 2014/05/20 17:47:27]

Then I recommend DCHECKing this condition. Also, line 534 handles the empty
case.

+    bool codec_matched = false;
+    for (size_t j = 0; j < supported_codecs.size(); ++j) {
+      if (!MatchPattern(static_cast<base::StringPiece>(codecs[i]),
+                        static_cast<base::StringPiece>(supported_codecs[j]))) {
+        continue;
+      }
+      if (codecs[i].find('.') != std::string::npos) {
+        if (EndsWith(codecs[i], ".", false))
+          return false;
+
+        // Check whether the suffix is hexadecimal.
+        std::vector<std::string> split_string;
+        base::SplitString(codecs[i], '.', &split_string);
+        const std::string& number = split_string.back();
+        for (size_t k = 0; k < number.length(); ++k) {
+          // Don't enforce case sensitivity, even though it's called for, as it
+          // would break some websites.
+          if (!IsHexDigit(number.at(k)))
+            return false;
+        }
+      }
+      codec_matched = true;
+      break;
+    }
+    if (!codec_matched)
+      return false;
+  }
+  return !codecs.empty();
+}
+
 void MimeUtil::InitializeMimeTypeMaps() {
   for (size_t i = 0; i < arraysize(supported_image_types); ++i)
     image_map_.insert(supported_image_types[i]);
 
   // Initialize the supported non-image types.
   for (size_t i = 0; i < arraysize(supported_non_image_types); ++i)
     non_image_map_.insert(supported_non_image_types[i]);
   for (size_t i = 0; i < arraysize(supported_certificate_types); ++i)
     non_image_map_.insert(supported_certificate_types[i].mime_type);
   for (size_t i = 0; i < arraysize(unsupported_text_types); ++i)
@@ skipping 50 matching lines @@
     MimeMappings codecs;
     for (size_t j = 0; j < mime_type_codecs.size(); ++j) {
 #if defined(OS_ANDROID)
       if (!IsCodecSupportedOnAndroid(mime_type_codecs[j]))
         continue;
 #endif
       codecs.insert(mime_type_codecs[j]);
     }
     strict_format_map_[format_codec_mappings[i].mime_type] = codecs;
   }
+  for (size_t i = 0; i < arraysize(format_mp4_codec_mappings); ++i) {
+    std::vector<std::string> mime_type_codecs;
+    ParseCodecString(
+        format_mp4_codec_mappings[i].codecs_list, &mime_type_codecs, false);
+
+    MimeExpressionMappings codecs;
+    for (size_t j = 0; j < mime_type_codecs.size(); ++j) {
+      codecs.push_back(mime_type_codecs[j]);
+    }
+    strict_mp4_format_map_[format_mp4_codec_mappings[i].mime_type] = codecs;
+  }
 }
 
 bool MimeUtil::IsSupportedImageMimeType(const std::string& mime_type) const {
   return image_map_.find(mime_type) != image_map_.end();
 }
 
 bool MimeUtil::IsSupportedMediaMimeType(const std::string& mime_type) const {
   return media_map_.find(mime_type) != media_map_.end();
 }
 
@@ skipping 162 matching lines @@
   for (std::vector<std::string>::iterator it = codecs_out->begin();
        it != codecs_out->end();
        ++it) {
     size_t found = it->find_first_of('.');
     if (found != std::string::npos)
       it->resize(found);
   }
 }
 
 bool MimeUtil::IsStrictMediaMimeType(const std::string& mime_type) const {
-  if (strict_format_map_.find(mime_type) == strict_format_map_.end())
+  if (strict_format_map_.find(mime_type) == strict_format_map_.end() &&
+      strict_mp4_format_map_.find(mime_type) == strict_mp4_format_map_.end())
     return false;
   return true;
 }
 
-bool MimeUtil::IsSupportedStrictMediaMimeType(
+CanPlayType MimeUtil::IsSupportedStrictMediaMimeType(
     const std::string& mime_type,
     const std::vector<std::string>& codecs) const {
   StrictMappings::const_iterator it = strict_format_map_.find(mime_type);
-  return (it != strict_format_map_.end()) &&
-      AreSupportedCodecs(it->second, codecs);
+  if (it != strict_format_map_.end() && AreSupportedCodecs(it->second, codecs))
+    return IsSupported;
+
+  StrictExpressionMappings::const_iterator iter =

[ddorwin, 2014/05/16 18:49:49]

I don't think "it" and "iter" should be used in the same function.

+      strict_mp4_format_map_.find(mime_type);
+  if ((iter != strict_mp4_format_map_.end()) &&
+      AreSupportedCodecsWithProfile(iter->second, codecs)) {
+    return MayBeSupported;
+  }
+
+  if (codecs.empty())

[ddorwin, 2014/05/16 18:49:49]

Ideally, this should bail early, but we also have to make sure the MIME type is
found.

It's concerning that we call AreSupported*Codecs without knowing whether it is
empty. Specifically, at 810, it's not clear whether we might return the wrong
value depending on how AreSupportedCodecs() handles the empty vector.

[AmoghBihani, 2014/05/16 19:18:01]

This was done specifically because mp3 containers do not expect any codec
parameter.
If we check this condition first then queries for audio/mp3 will return "maybe"
although they must return "probably".
You can view the change in
https://codereview.chromium.org/228823003/diff/100001/content/renderer/render...

AreSupportedCodecs handles this automatically. line 493 checks for the above
mentioned scenario. In other cases, loop on line 496 won't be executed and line
500 will take care of the rest.

+    return MayBeSupported;
+
+  return IsNotSupported;
 }
 
 void MimeUtil::RemoveProprietaryMediaTypesAndCodecsForTests() {
   for (size_t i = 0; i < arraysize(proprietary_media_types); ++i) {
     non_image_map_.erase(proprietary_media_types[i]);
     media_map_.erase(proprietary_media_types[i]);
   }
   for (size_t i = 0; i < arraysize(proprietary_media_codecs); ++i)
     codecs_map_.erase(proprietary_media_codecs[i]);
 }
@@ skipping 57 matching lines @@
 }
 
 bool AreSupportedMediaCodecs(const std::vector<std::string>& codecs) {
   return g_mime_util.Get().AreSupportedMediaCodecs(codecs);
 }
 
 bool IsStrictMediaMimeType(const std::string& mime_type) {
   return g_mime_util.Get().IsStrictMediaMimeType(mime_type);
 }
 
-bool IsSupportedStrictMediaMimeType(const std::string& mime_type,
-                                    const std::vector<std::string>& codecs) {
+CanPlayType IsSupportedStrictMediaMimeType(
+    const std::string& mime_type,
+    const std::vector<std::string>& codecs) {
   return g_mime_util.Get().IsSupportedStrictMediaMimeType(mime_type, codecs);
 }
 
 void ParseCodecString(const std::string& codecs,
                       std::vector<std::string>* codecs_out,
                       const bool strip) {
   g_mime_util.Get().ParseCodecString(codecs, codecs_out, strip);
 }
 
 namespace {
@@ skipping 228 matching lines @@
   post_data->append("\r\n" + value + "\r\n");
 }
 
 void AddMultipartFinalDelimiterForUpload(const std::string& mime_boundary,
                                          std::string* post_data) {
   DCHECK(post_data);
   post_data->append("--" + mime_boundary + "--\r\n");
 }
 
 }  // namespace net