Add UMA stats for audio/video containers.

media/filters/ffmpeg_glue.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 "media/filters/ffmpeg_glue.h"
-

[xhwang, 2013/04/29 21:00:25]

keep this empty line:
http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml?showone=Names_...

[jrummell, 2013/04/30 21:36:50]

Done.

 #include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/synchronization/lock.h"
+#include "media/base/container_names.h"
 #include "media/ffmpeg/ffmpeg_common.h"
 
 namespace media {
 
 // Internal buffer size used by AVIO for reading.
 // TODO(dalecurtis): Experiment with this buffer size and measure impact on
 // performance.  Currently we want to use 32kb to preserve existing behavior
 // with the previous URLProtocol based approach.
 enum { kBufferSize = 32 * 1024 };
 
@@ skipping 96 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(FFmpegInitializer);
 };
 
 void FFmpegGlue::InitializeFFmpeg() {
   static base::LazyInstance<FFmpegInitializer>::Leaky li =
       LAZY_INSTANCE_INITIALIZER;
   CHECK(li.Get().initialized());
 }
 
 FFmpegGlue::FFmpegGlue(FFmpegURLProtocol* protocol)
-    : open_called_(false) {
+    : open_called_(false),
+      protocol_(protocol) {
   InitializeFFmpeg();
 
   // Initialize an AVIOContext using our custom read and seek operations.  Don't
   // keep pointers to the buffer since FFmpeg may reallocate it on the fly.  It
   // will be cleaned up
   format_context_ = avformat_alloc_context();
   avio_context_.reset(avio_alloc_context(
       static_cast<unsigned char*>(av_malloc(kBufferSize)), kBufferSize, 0,
       protocol, &AVIOReadOperation, NULL, &AVIOSeekOperation));
 
@@ skipping 13 matching lines @@
 
 bool FFmpegGlue::OpenContext() {
   DCHECK(!open_called_) << "OpenContext() should't be called twice.";
 
   // If avformat_open_input() is called we have to take a slightly different
   // destruction path to avoid double frees.
   open_called_ = true;
 
   // By passing NULL for the filename (second parameter) we are telling FFmpeg
   // to use the AVIO context we setup from the AVFormatContext structure.
-  return avformat_open_input(&format_context_, NULL, NULL, NULL) == 0;
+  int result = avformat_open_input(&format_context_, NULL, NULL, NULL);
+  ContainerNames container;
+  if (result == 0) {
+    // FFmpeg decoded the container, so report what it found
+    container.LogContainer(format_context_->iformat->name);
+    return true;
+  }
+
+  // Stream was not recognized by FFmpeg. Re-read part of the stream and see if
+  // the stream can be recognized. Unfortunately FFmpeg has released the buffer
+  // where it read the header, so we need to read it again. We leave the stream
+  // position unchanged.
+  int64 pos;
+  uint8 buf[8192];

[xhwang, 2013/04/29 21:00:25]

This code path only happens in the failure case. But we always use a 8k buffer
on the stack, which seems inefficient. Allocate this on the heap?

[jrummell, 2013/04/30 21:36:50]

Done.

+
+  protocol_->GetPosition(&pos);
+  protocol_->SetPosition(0);
+  int numRead = protocol_->Read(sizeof(buf), buf);
+  protocol_->SetPosition(pos);
+  container.LogContainer(buf, numRead);
+  return false;
 }
 
 FFmpegGlue::~FFmpegGlue() {
   // In the event of avformat_open_input() failure, FFmpeg may sometimes free
   // our AVFormatContext behind the scenes, but leave the buffer alive.  It will
   // helpfully set |format_context_| to NULL in this case.
   if (!format_context_) {
     av_free(avio_context_->buffer);
     return;
   }
@@ skipping 24 matching lines @@
         avcodec_close(stream->codec);
       }
     }
   }
 
   avformat_close_input(&format_context_);
   av_free(avio_context_->buffer);
 }
 
 }  // namespace media