Encrypted Media: Enforcing the CDM to decode audio into S16 integers.

media/filters/decrypting_audio_decoder.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/decrypting_audio_decoder.h"
 
 #include <cstdlib>
 
 #include "base/bind.h"
 #include "base/callback_helpers.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/message_loop_proxy.h"
 #include "media/base/audio_decoder_config.h"
 #include "media/base/bind_to_loop.h"
 #include "media/base/buffers.h"
 #include "media/base/data_buffer.h"
 #include "media/base/decoder_buffer.h"
 #include "media/base/decryptor.h"
 #include "media/base/demuxer_stream.h"
 #include "media/base/pipeline.h"
 
 namespace media {
 
 #define BIND_TO_LOOP(function) \
     media::BindToLoop(message_loop_, base::Bind(function, this))
 
+const int DecryptingAudioDecoder::kSupportedBitsPerChannel = 16;
+
 static inline bool IsOutOfSync(const base::TimeDelta& timestamp_1,
                                const base::TimeDelta& timestamp_2) {
   // Out of sync of 100ms would be pretty noticeable and we should keep any
   // drift below that.
   const int64 kOutOfSyncThresholdInMicroseconds = 100000;
   return std::abs(timestamp_1.InMicroseconds() - timestamp_2.InMicroseconds()) >
          kOutOfSyncThresholdInMicroseconds;
 }
 
 DecryptingAudioDecoder::DecryptingAudioDecoder(
@@ skipping 125 matching lines @@
 void DecryptingAudioDecoder::SetDecryptor(Decryptor* decryptor) {
   DVLOG(2) << "SetDecryptor()";
   DCHECK(message_loop_->BelongsToCurrentThread());
   DCHECK_EQ(state_, kDecryptorRequested) << state_;
   DCHECK(!init_cb_.is_null());
   DCHECK(!set_decryptor_ready_cb_.is_null());
 
   set_decryptor_ready_cb_.Reset();
   decryptor_ = decryptor;
 
+  const AudioDecoderConfig& input_config =
+      demuxer_stream_->audio_decoder_config();
   scoped_ptr<AudioDecoderConfig> scoped_config(new AudioDecoderConfig());
-  scoped_config->CopyFrom(demuxer_stream_->audio_decoder_config());
+  scoped_config->Initialize(input_config.codec(),
+                            kSampleFormatS16,
+                            input_config.channel_layout(),
+                            input_config.samples_per_second(),
+                            input_config.extra_data(),
+                            input_config.extra_data_size(),
+                            input_config.is_encrypted(),
+                            false);
 
   state_ = kPendingDecoderInit;
   decryptor_->InitializeAudioDecoder(
       scoped_config.Pass(),
       BIND_TO_LOOP(&DecryptingAudioDecoder::FinishInitialization));
 }
 
 void DecryptingAudioDecoder::FinishInitialization(bool success) {
   DVLOG(2) << "FinishInitialization()";
   DCHECK(message_loop_->BelongsToCurrentThread());
   DCHECK_EQ(state_, kPendingDecoderInit) << state_;
   DCHECK(!init_cb_.is_null());
   DCHECK(reset_cb_.is_null());  // No Reset() before initialization finished.
   DCHECK(read_cb_.is_null());  // No Read() before initialization finished.
 
   if (!success) {
     base::ResetAndReturn(&init_cb_).Run(DECODER_ERROR_NOT_SUPPORTED);
     state_ = kDecodeFinished;
     return;
   }
 
   // Success!
-  const AudioDecoderConfig& config = demuxer_stream_->audio_decoder_config();
-  bits_per_channel_ = config.bits_per_channel();
-  channel_layout_ = config.channel_layout();
-  samples_per_second_ = config.samples_per_second();
-  const int kBitsPerByte = 8;
-  bytes_per_sample_ = ChannelLayoutToChannelCount(channel_layout_) *
-      bits_per_channel_ / kBitsPerByte;
+  SetDecoderConfig();
 
   decryptor_->RegisterNewKeyCB(
       Decryptor::kAudio, BIND_TO_LOOP(&DecryptingAudioDecoder::OnKeyAdded));
 
   state_ = kIdle;
   base::ResetAndReturn(&init_cb_).Run(PIPELINE_OK);
 }
 
 void DecryptingAudioDecoder::FinishConfigChange(bool success) {
   DVLOG(2) << "FinishConfigChange()";
   DCHECK(message_loop_->BelongsToCurrentThread());
   DCHECK_EQ(state_, kPendingConfigChange) << state_;
   DCHECK(!read_cb_.is_null());
 
   if (!success) {
     base::ResetAndReturn(&read_cb_).Run(kDecodeError, NULL);
     state_ = kDecodeFinished;
     if (!reset_cb_.is_null())
       base::ResetAndReturn(&reset_cb_).Run();
     return;
   }
 
   // Config change succeeded.
+  SetDecoderConfig();

[DaleCurtis, 2013/01/10 01:24:35]

Is this a bug fix?

[xhwang, 2013/01/10 18:17:23]

Hmm, yes, filed bug and split this change to
https://codereview.chromium.org/11824066/

+
   if (!reset_cb_.is_null()) {
     base::ResetAndReturn(&read_cb_).Run(kAborted, NULL);
     DoReset();
     return;
   }
 
   state_ = kPendingDemuxerRead;
   ReadFromDemuxerStream();
 }
 
@@ skipping 41 matching lines @@
   }
 
   DVLOG(3) << "DoDecryptAndDecodeBuffer()";
   DCHECK_EQ(state_, kPendingDemuxerRead) << state_;
   DCHECK(!read_cb_.is_null());
   DCHECK_EQ(buffer != NULL, status == DemuxerStream::kOk) << status;
 
   if (status == DemuxerStream::kConfigChanged) {
     DVLOG(2) << "DoDecryptAndDecodeBuffer() - kConfigChanged";
 
-    scoped_ptr<AudioDecoderConfig> scoped_config(new AudioDecoderConfig());
-    scoped_config->CopyFrom(demuxer_stream_->audio_decoder_config());
+  const AudioDecoderConfig& input_config =
+      demuxer_stream_->audio_decoder_config();
+  scoped_ptr<AudioDecoderConfig> scoped_config(new AudioDecoderConfig());
+  scoped_config->Initialize(input_config.codec(),
+                            kSampleFormatS16,
+                            input_config.channel_layout(),
+                            input_config.samples_per_second(),
+                            input_config.extra_data(),
+                            input_config.extra_data_size(),
+                            input_config.is_encrypted(),
+                            false);
 
     state_ = kPendingConfigChange;
     decryptor_->DeinitializeDecoder(Decryptor::kAudio);
     decryptor_->InitializeAudioDecoder(
         scoped_config.Pass(), BindToCurrentLoop(base::Bind(
             &DecryptingAudioDecoder::FinishConfigChange, this)));
     return;
   }
 
   if (!reset_cb_.is_null()) {
@@ skipping 140 matching lines @@
 
 void DecryptingAudioDecoder::DoReset() {
   DCHECK(init_cb_.is_null());
   DCHECK(read_cb_.is_null());
   output_timestamp_base_ = kNoTimestamp();
   total_samples_decoded_ = 0;
   state_ = kIdle;
   base::ResetAndReturn(&reset_cb_).Run();
 }
 
+void DecryptingAudioDecoder::SetDecoderConfig() {
+  const AudioDecoderConfig& config = demuxer_stream_->audio_decoder_config();
+  bits_per_channel_ = kSupportedBitsPerChannel;
+  channel_layout_ = config.channel_layout();
+  samples_per_second_ = config.samples_per_second();
+  const int kBitsPerByte = 8;
+  bytes_per_sample_ = ChannelLayoutToChannelCount(channel_layout_) *
+      bits_per_channel_ / kBitsPerByte;
+  output_timestamp_base_ = kNoTimestamp();
+  total_samples_decoded_ = 0;
+}
+
 void DecryptingAudioDecoder::EnqueueFrames(
     const Decryptor::AudioBuffers& frames) {
   queued_audio_frames_ = frames;
 
   for (Decryptor::AudioBuffers::iterator iter = queued_audio_frames_.begin();
       iter != queued_audio_frames_.end();
       ++iter) {
     scoped_refptr<Buffer>& frame = *iter;
 
     DCHECK(!frame->IsEndOfStream()) << "EOS frame returned.";
@@ skipping 24 matching lines @@
 
 base::TimeDelta DecryptingAudioDecoder::NumberOfSamplesToDuration(
     int number_of_samples) const {
   DCHECK(samples_per_second_);
   return base::TimeDelta::FromMicroseconds(base::Time::kMicrosecondsPerSecond *
                                            number_of_samples /
                                            samples_per_second_);
 }
 
 }  // namespace media