Roll FFMpeg for M26. Fix ffmpeg float audio decoding.

media/filters/ffmpeg_audio_decoder.cc

Index: media/filters/ffmpeg_audio_decoder.cc
diff --git a/media/filters/ffmpeg_audio_decoder.cc b/media/filters/ffmpeg_audio_decoder.cc
index 5384d63c48874a70c01b8c00aece2eebe5392d5b..3f1e81a37f7ddba6950a455336580c8c36eacc0f 100644
--- a/media/filters/ffmpeg_audio_decoder.cc
+++ b/media/filters/ffmpeg_audio_decoder.cc
@@ -8,6 +8,7 @@
 #include "base/callback_helpers.h"
 #include "base/location.h"
 #include "base/message_loop_proxy.h"
+#include "media/base/audio_bus.h"
 #include "media/base/audio_decoder_config.h"
 #include "media/base/audio_timestamp_helper.h"
 #include "media/base/data_buffer.h"
@@ -283,6 +284,10 @@ bool FFmpegAudioDecoder::ConfigureDecoder() {
   codec_context_ = avcodec_alloc_context3(NULL);
   AudioDecoderConfigToAVCodecContext(config, codec_context_);
 
+  // MP3 decodes to S16P which we don't support, tell it to use S16 instead.
+  if (codec_context_->sample_fmt == AV_SAMPLE_FMT_S16P)
+    codec_context_->request_sample_fmt = AV_SAMPLE_FMT_S16;
+
   AVCodec* codec = avcodec_find_decoder(codec_context_->codec_id);
   if (!codec || avcodec_open2(codec_context_, codec, NULL) < 0) {
     DLOG(ERROR) << "Could not initialize audio decoder: "
@@ -290,6 +295,26 @@ bool FFmpegAudioDecoder::ConfigureDecoder() {
     return false;
   }
 
+  // Ensure avcodec_open2() respected our format request.
+  if (codec_context_->sample_fmt == AV_SAMPLE_FMT_S16P) {
+    DLOG(ERROR) << "Unable to configure a supported sample format: "
+                << codec_context_->sample_fmt;
+    return false;
+  }
+
+  // Some codecs will only output float data, so we need to convert to integer
+  // before returning the decoded buffer.
+  if (codec_context_->sample_fmt == AV_SAMPLE_FMT_FLTP ||
+      codec_context_->sample_fmt == AV_SAMPLE_FMT_FLT) {
+    // Preallocate the AudioBus for float conversions.  We can treat interleaved
+    // float data as a single planar channel since our output is expected in an
+    // interleaved format anyways.
+    int channels = codec_context_->channels;
+    if (codec_context_->sample_fmt == AV_SAMPLE_FMT_FLT)
+      channels = 1;
+    converter_bus_ = AudioBus::CreateWrapper(channels);
+  }
+
   // Success!
   av_frame_ = avcodec_alloc_frame();
   bits_per_channel_ = config.bits_per_channel();
@@ -297,6 +322,7 @@ bool FFmpegAudioDecoder::ConfigureDecoder() {
   samples_per_second_ = config.samples_per_second();
   output_timestamp_helper_.reset(new AudioTimestampHelper(
       config.bytes_per_frame(), config.samples_per_second()));
+  bytes_per_frame_ = config.bytes_per_frame();
   return true;
 }
 
@@ -374,7 +400,6 @@ void FFmpegAudioDecoder::RunDecodeLoop(
       }
     }
 
-    const uint8* decoded_audio_data = NULL;
     int decoded_audio_size = 0;
     if (frame_decoded) {
       int output_sample_rate = av_frame_->sample_rate;
@@ -388,24 +413,64 @@ void FFmpegAudioDecoder::RunDecodeLoop(
         break;
       }
 
-      decoded_audio_data = av_frame_->data[0];
       decoded_audio_size = av_samples_get_buffer_size(
           NULL, codec_context_->channels, av_frame_->nb_samples,
           codec_context_->sample_fmt, 1);
+      // If we're decoding into float, adjust audio size.
+      if (converter_bus_ && bits_per_channel_ / 8 != sizeof(float)) {
+        DCHECK(codec_context_->sample_fmt == AV_SAMPLE_FMT_FLT ||
+               codec_context_->sample_fmt == AV_SAMPLE_FMT_FLTP);
+        decoded_audio_size *=
+            static_cast<float>(bits_per_channel_ / 8) / sizeof(float);
+      }
     }
 
-    scoped_refptr<DataBuffer> output;
-
+    int start_sample = 0;
     if (decoded_audio_size > 0 && output_bytes_to_drop_ > 0) {
+      DCHECK_EQ(decoded_audio_size % bytes_per_frame_, 0)
+          << "Decoder didn't output full frames";
+
       int dropped_size = std::min(decoded_audio_size, output_bytes_to_drop_);
-      decoded_audio_data += dropped_size;
+      start_sample = dropped_size / bytes_per_frame_;
       decoded_audio_size -= dropped_size;
       output_bytes_to_drop_ -= dropped_size;
     }
 
+    scoped_refptr<DataBuffer> output;
     if (decoded_audio_size > 0) {
-      // Copy the audio samples into an output buffer.
-      output = new DataBuffer(decoded_audio_data, decoded_audio_size);
+      DCHECK_EQ(decoded_audio_size % bytes_per_frame_, 0)
+          << "Decoder didn't output full frames";
+
+      // Convert float data using an AudioBus.
+      if (converter_bus_) {
+        // Setup the AudioBus as a wrapper of the AVFrame data and then use
+        // AudioBus::ToInterleaved() to convert the data as necessary.
+        int skip_frames = start_sample;
+        int total_frames = av_frame_->nb_samples - start_sample;
+        if (codec_context_->sample_fmt == AV_SAMPLE_FMT_FLT) {
+          DCHECK_EQ(converter_bus_->channels(), 1);
+          total_frames *= codec_context_->channels;
+          skip_frames *= codec_context_->channels;
+        }
+        converter_bus_->set_frames(total_frames);
+        DCHECK_EQ(decoded_audio_size,
+                  converter_bus_->frames() * bytes_per_frame_);
+
+        for (int i = 0; i < converter_bus_->channels(); ++i) {
+          converter_bus_->SetChannelData(i, reinterpret_cast<float*>(
+              av_frame_->extended_data[i]) + skip_frames);
+        }
+
+        output = new DataBuffer(decoded_audio_size);
+        output->SetDataSize(decoded_audio_size);
+        converter_bus_->ToInterleaved(
+            converter_bus_->frames(), bits_per_channel_ / 8,
+            output->GetWritableData());
+      } else {
+        output = new DataBuffer(
+            av_frame_->extended_data[0] + start_sample * bytes_per_frame_,
+            decoded_audio_size);
+      }
       output->SetTimestamp(output_timestamp_helper_->GetTimestamp());
       output->SetDuration(
           output_timestamp_helper_->GetDuration(decoded_audio_size));