Merge branch 'master' into mailnews-work

1 files changed, 87 insertions, 36 deletions

diff --git a/media/libcubeb/src/cubeb_resampler_internal.h b/media/libcubeb/src/cubeb_resampler_internal.h
index 3c37a04b9..fb69992ff 100644
--- a/media/libcubeb/src/cubeb_resampler_internal.h
+++ b/media/libcubeb/src/cubeb_resampler_internal.h
@@ -39,6 +39,13 @@ MOZ_END_STD_NAMESPACE
 
 /* This header file contains the internal C++ API of the resamplers, for testing. */
 
+// When dropping audio input frames to prevent building
+// an input delay, this function returns the number of frames
+// to keep in the buffer.
+// @parameter sample_rate The sample rate of the stream.
+// @return A number of frames to keep.
+uint32_t min_buffered_audio_frame(uint32_t sample_rate);
+
 int to_speex_quality(cubeb_resampler_quality q);
 
 struct cubeb_resampler {
@@ -48,31 +55,6 @@ struct cubeb_resampler {
   virtual ~cubeb_resampler() {}
 };
 
-class noop_resampler : public cubeb_resampler {
-public:
-  noop_resampler(cubeb_stream * s,
-                 cubeb_data_callback cb,
-                 void * ptr)
-    : stream(s)
-    , data_callback(cb)
-    , user_ptr(ptr)
-  {
-  }
-
-  virtual long fill(void * input_buffer, long * input_frames_count,
-                    void * output_buffer, long output_frames);
-
-  virtual long latency()
-  {
-    return 0;
-  }
-
-private:
-  cubeb_stream * const stream;
-  const cubeb_data_callback data_callback;
-  void * const user_ptr;
-};
-
 /** Base class for processors. This is just used to share methods for now. */
 class processor {
 public:
@@ -80,11 +62,11 @@ public:
     : channels(channels)
   {}
 protected:
-  size_t frames_to_samples(size_t frames)
+  size_t frames_to_samples(size_t frames) const
   {
     return frames * channels;
   }
-  size_t samples_to_frames(size_t samples)
+  size_t samples_to_frames(size_t samples) const
   {
     assert(!(samples % channels));
     return samples / channels;
@@ -93,6 +75,43 @@ protected:
   const uint32_t channels;
 };
 
+template<typename T>
+class passthrough_resampler : public cubeb_resampler
+                            , public processor {
+public:
+  passthrough_resampler(cubeb_stream * s,
+                        cubeb_data_callback cb,
+                        void * ptr,
+                        uint32_t input_channels,
+                        uint32_t sample_rate);
+
+  virtual long fill(void * input_buffer, long * input_frames_count,
+                    void * output_buffer, long output_frames);
+
+  virtual long latency()
+  {
+    return 0;
+  }
+
+  void drop_audio_if_needed()
+  {
+    uint32_t to_keep = min_buffered_audio_frame(sample_rate);
+    uint32_t available = samples_to_frames(internal_input_buffer.length());
+    if (available > to_keep) {
+      internal_input_buffer.pop(nullptr, frames_to_samples(available - to_keep));
+    }
+  }
+
+private:
+  cubeb_stream * const stream;
+  const cubeb_data_callback data_callback;
+  void * const user_ptr;
+  /* This allows to buffer some input to account for the fact that we buffer
+   * some inputs. */
+  auto_array<T> internal_input_buffer;
+  uint32_t sample_rate;
+};
+
 /** Bidirectional resampler, can resample an input and an output stream, or just
  * an input stream or output stream. In this case a delay is inserted in the
  * opposite direction to keep the streams synchronized. */
@@ -138,6 +157,7 @@ private:
   cubeb_stream * const stream;
   const cubeb_data_callback data_callback;
   void * const user_ptr;
+  bool draining = false;
 };
 
 /** Handles one way of a (possibly) duplex resampler, working on interleaved
@@ -163,6 +183,7 @@ public:
                                 int quality)
   : processor(channels)
   , resampling_ratio(static_cast<float>(source_rate) / target_rate)
+  , source_rate(source_rate)
   , additional_latency(0)
   , leftover_samples(0)
   {
@@ -221,7 +242,7 @@ public:
 
   /** Returns a buffer containing exactly `output_frame_count` resampled frames.
     * The consumer should not hold onto the pointer. */
-  T * output(size_t output_frame_count)
+  T * output(size_t output_frame_count, size_t * input_frames_used)
   {
     if (resampling_out_buffer.capacity() < frames_to_samples(output_frame_count)) {
       resampling_out_buffer.reserve(frames_to_samples(output_frame_count));
@@ -238,6 +259,7 @@ public:
     /* This shifts back any unresampled samples to the beginning of the input
        buffer. */
     resampling_in_buffer.pop(nullptr, frames_to_samples(in_len));
+    *input_frames_used = in_len;
 
     return resampling_out_buffer.data();
   }
@@ -261,7 +283,7 @@ public:
    * exactly `output_frame_count` resampled frames. This can return a number
    * slightly bigger than what is strictly necessary, but it guaranteed that the
    * number of output frames will be exactly equal. */
-  uint32_t input_needed_for_output(uint32_t output_frame_count)
+  uint32_t input_needed_for_output(uint32_t output_frame_count) const
   {
     int32_t unresampled_frames_left = samples_to_frames(resampling_in_buffer.length());
     int32_t resampled_frames_left = samples_to_frames(resampling_out_buffer.length());
@@ -294,6 +316,16 @@ public:
     resampling_in_buffer.set_length(leftover_samples +
                                     frames_to_samples(written_frames));
   }
+
+  void drop_audio_if_needed()
+  {
+    // Keep at most 100ms buffered.
+    uint32_t available = samples_to_frames(resampling_in_buffer.length());
+    uint32_t to_keep = min_buffered_audio_frame(source_rate);
+    if (available > to_keep) {
+      resampling_in_buffer.pop(nullptr, frames_to_samples(available - to_keep));
+    }
+  }
 private:
   /** Wrapper for the speex resampling functions to have a typed
     * interface. */
@@ -330,6 +362,7 @@ private:
   SpeexResamplerState * speex_resampler;
   /** Source rate / target rate. */
   const float resampling_ratio;
+  const uint32_t source_rate;
   /** Storage for the input frames, to be resampled. Also contains
    * any unresampled frames after resampling. */
   auto_array<T> resampling_in_buffer;
@@ -348,11 +381,13 @@ class delay_line : public processor {
 public:
   /** Constructor
    * @parameter frames the number of frames of delay.
-   * @parameter channels the number of channels of this delay line. */
-  delay_line(uint32_t frames, uint32_t channels)
+   * @parameter channels the number of channels of this delay line.
+   * @parameter sample_rate sample-rate of the audio going through this delay line */
+  delay_line(uint32_t frames, uint32_t channels, uint32_t sample_rate)
     : processor(channels)
     , length(frames)
     , leftover_samples(0)
+    , sample_rate(sample_rate)
   {
     /* Fill the delay line with some silent frames to add latency. */
     delay_input_buffer.push_silence(frames * channels);
@@ -375,7 +410,7 @@ public:
    * @parameter frames_needed the number of frames to be returned.
    * @return a buffer containing the delayed frames. The consumer should not
    * hold onto the pointer. */
-  T * output(uint32_t frames_needed)
+  T * output(uint32_t frames_needed, size_t * input_frames_used)
   {
     if (delay_output_buffer.capacity() < frames_to_samples(frames_needed)) {
       delay_output_buffer.reserve(frames_to_samples(frames_needed));
@@ -385,6 +420,7 @@ public:
     delay_output_buffer.push(delay_input_buffer.data(),
                              frames_to_samples(frames_needed));
     delay_input_buffer.pop(nullptr, frames_to_samples(frames_needed));
+    *input_frames_used = frames_needed;
 
     return delay_output_buffer.data();
   }
@@ -426,7 +462,7 @@ public:
    * @parameter frames_needed the number of frames one want to write into the
    * delay_line
    * @returns the number of frames one will get. */
-  size_t input_needed_for_output(uint32_t frames_needed)
+  size_t input_needed_for_output(uint32_t frames_needed) const
   {
     return frames_needed;
   }
@@ -441,6 +477,15 @@ public:
   {
     return length;
   }
+
+  void drop_audio_if_needed()
+  {
+    size_t available = samples_to_frames(delay_input_buffer.length());
+    uint32_t to_keep = min_buffered_audio_frame(sample_rate);
+    if (available > to_keep) {
+      delay_input_buffer.pop(nullptr, frames_to_samples(available - to_keep));
+    }
+  }
 private:
   /** The length, in frames, of this delay line */
   uint32_t length;
@@ -452,6 +497,7 @@ private:
   /** The output buffer. This is only ever used if using the ::output with a
    * single argument. */
   auto_array<T> delay_output_buffer;
+  uint32_t sample_rate;
 };
 
 /** This sits behind the C API and is more typed. */
@@ -480,7 +526,10 @@ cubeb_resampler_create_internal(cubeb_stream * stream,
       (output_params && output_params->rate == target_rate)) ||
       (input_params && !output_params && (input_params->rate == target_rate)) ||
       (output_params && !input_params && (output_params->rate == target_rate))) {
-    return new noop_resampler(stream, callback, user_ptr);
+    return new passthrough_resampler<T>(stream, callback,
+                                        user_ptr,
+                                        input_params ? input_params->channels : 0,
+                                        target_rate);
   }
 
   /* Determine if we need to resampler one or both directions, and create the
@@ -512,13 +561,15 @@ cubeb_resampler_create_internal(cubeb_stream * stream,
    * other direction so that the streams are synchronized. */
   if (input_resampler && !output_resampler && input_params && output_params) {
     output_delay.reset(new delay_line<T>(input_resampler->latency(),
-                                         output_params->channels));
+                                         output_params->channels,
+                                         output_params->rate));
     if (!output_delay) {
       return NULL;
     }
   } else if (output_resampler && !input_resampler && input_params && output_params) {
     input_delay.reset(new delay_line<T>(output_resampler->latency(),
-                                        input_params->channels));
+                                        input_params->channels,
+                                        output_params->rate));
     if (!input_delay) {
       return NULL;
     }