When an ALSA input goes away, replace it by silence.

[nageru] / audio_mixer.h

diff --git a/audio_mixer.h b/audio_mixer.h
index c845a26608aec82a3534826aacb86fd418d2ded1..855295dcd60f0bf207f435c75484a763eba77b89 100644 (file)
--- a/audio_mixer.h
+++ b/audio_mixer.h
@@ -93,6 +93,13 @@ public:
        bool add_audio(DeviceSpec device_spec, const uint8_t *data, unsigned num_samples, bmusb::AudioFormat audio_format, int64_t frame_length);
        bool add_silence(DeviceSpec device_spec, unsigned samples_per_frame, unsigned num_frames, int64_t frame_length);
 
+       // If a given device is offline for whatever reason and cannot deliver audio
+       // (by means of add_audio() or add_silence()), you can call put it in silence mode,
+       // where it will be taken to only output silence. Note that when taking it _out_
+       // of silence mode, the resampler will be reset, so that old audio will not
+       // affect it. Same true/false behavior as add_audio().
+       bool silence_card(DeviceSpec device_spec, bool silence);
+
        std::vector<float> get_output(double pts, unsigned num_samples, ResamplingQueue::RateAdjustmentPolicy rate_adjustment_policy);
 
        void set_fader_volume(unsigned bus_index, float level_db) { fader_volume_db[bus_index] = level_db; }
@@ -263,6 +270,7 @@ private:
                unsigned capture_frequency = OUTPUT_FREQUENCY;
                // Which channels we consider interesting (ie., are part of some input_mapping).
                std::set<unsigned> interesting_channels;
+               bool silenced = false;
        };
 
        const AudioDevice *find_audio_device(DeviceSpec device_spec) const