* Extracted method void AudioDiskstream::process_varispeed_playback(nframes_t nframes, boost::shared_ptr<ChannelList> c)
from AudioDiskstream::process git-svn-id: svn://localhost/ardour2/branches/3.0@4396 d708f5d6-7413-0410-9779-e7cbd77b26cf
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@ -175,7 +175,7 @@ class AudioDiskstream : public Diskstream
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protected:
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friend class AudioTrack;
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int process (nframes_t transport_frame, nframes_t nframes, nframes_t offset, bool can_record, bool rec_monitors_input);
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int process (nframes_t transport_frame, nframes_t nframes, nframes_t offset, bool can_record, bool rec_monitors_input);
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bool commit (nframes_t nframes);
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private:
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@ -216,6 +216,8 @@ class AudioDiskstream : public Diskstream
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typedef std::vector<ChannelInfo*> ChannelList;
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void process_varispeed_playback(nframes_t nframes, boost::shared_ptr<ChannelList> c);
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/* The two central butler operations */
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int do_flush (Session::RunContext context, bool force = false);
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int do_refill () { return _do_refill(_mixdown_buffer, _gain_buffer); }
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@ -226,6 +228,7 @@ class AudioDiskstream : public Diskstream
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nframes_t& start, nframes_t cnt,
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ChannelInfo* channel_info, int channel, bool reversed);
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void finish_capture (bool rec_monitors_input, boost::shared_ptr<ChannelList>);
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void transport_stopped (struct tm&, time_t, bool abort);
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void transport_looped (nframes_t transport_frame);
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@ -779,60 +779,7 @@ AudioDiskstream::process (nframes_t transport_frame, nframes_t nframes, nframes_
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}
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if (rec_nframes == 0 && _actual_speed != 1.0f && _actual_speed != -1.0f) {
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// the idea behind phase is that when the speed is not 1.0, we have to
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// interpolate between samples and then we have to store where we thought we were.
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// rather than being at sample N or N+1, we were at N+0.8792922
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// so the "phase" element, if you want to think about this way,
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// varies from 0 to 1, representing the "offset" between samples
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uint64_t phase = last_phase;
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int64_t phi_delta;
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nframes_t i = 0;
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// Linearly interpolate into the alt buffer
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// using 40.24 fixp maths
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//
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// Fixedpoint is just an integer with an implied scaling factor.
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// In 40.24 the scaling factor is 2^24 = 16777216,
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// so a value of 10*2^24 (in integer space) is equivalent to 10.0.
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//
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// The advantage is that addition and modulus [like x = (x + y) % 2^40]
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// has no rounding errors and no drift, and just requires a single integer add.
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// (swh)
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const int64_t fractional_part_mask = 0xFFFFFF;
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const Sample binary_scaling_factor = 16777216.0f;
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// phi = fixed point speed
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if (phi != target_phi) {
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phi_delta = ((int64_t)(target_phi - phi)) / nframes;
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} else {
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phi_delta = 0;
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}
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for (chan = c->begin(); chan != c->end(); ++chan) {
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Sample fractional_part;
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ChannelInfo* chaninfo (*chan);
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i = 0;
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phase = last_phase;
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for (nframes_t outsample = 0; outsample < nframes; ++outsample) {
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i = phase >> 24;
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fractional_part = (phase & fractional_part_mask) / binary_scaling_factor;
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chaninfo->speed_buffer[outsample] =
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chaninfo->current_playback_buffer[i] * (1.0f - fractional_part) +
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chaninfo->current_playback_buffer[i+1] * fractional_part;
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phase += phi + phi_delta;
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}
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chaninfo->current_playback_buffer = chaninfo->speed_buffer;
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}
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playback_distance = i; // + 1;
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last_phase = (phase & fractional_part_mask);
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process_varispeed_playback(nframes, c);
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} else {
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playback_distance = nframes;
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}
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@ -859,6 +806,69 @@ AudioDiskstream::process (nframes_t transport_frame, nframes_t nframes, nframes_
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return ret;
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}
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void
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AudioDiskstream::process_varispeed_playback(nframes_t nframes, boost::shared_ptr<ChannelList> c)
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{
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ChannelList::iterator chan;
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// the idea behind phase is that when the speed is not 1.0, we have to
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// interpolate between samples and then we have to store where we thought we were.
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// rather than being at sample N or N+1, we were at N+0.8792922
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// so the "phase" element, if you want to think about this way,
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// varies from 0 to 1, representing the "offset" between samples
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uint64_t phase = last_phase;
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// acceleration
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int64_t phi_delta;
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// index in the input buffers
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nframes_t i = 0;
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// Linearly interpolate into the speed buffer
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// using 40.24 fixed point math
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//
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// Fixed point is just an integer with an implied scaling factor.
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// In 40.24 the scaling factor is 2^24 = 16777216,
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// so a value of 10*2^24 (in integer space) is equivalent to 10.0.
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//
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// The advantage is that addition and modulus [like x = (x + y) % 2^40]
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// have no rounding errors and no drift, and just require a single integer add.
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// (swh)
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const int64_t fractional_part_mask = 0xFFFFFF;
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const Sample binary_scaling_factor = 16777216.0f;
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// phi = fixed point speed
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if (phi != target_phi) {
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phi_delta = ((int64_t)(target_phi - phi)) / nframes;
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} else {
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phi_delta = 0;
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}
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for (chan = c->begin(); chan != c->end(); ++chan) {
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Sample fractional_phase_part;
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ChannelInfo* chaninfo (*chan);
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i = 0;
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phase = last_phase;
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for (nframes_t outsample = 0; outsample < nframes; ++outsample) {
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i = phase >> 24;
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fractional_phase_part = (phase & fractional_part_mask) / binary_scaling_factor;
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chaninfo->speed_buffer[outsample] =
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chaninfo->current_playback_buffer[i] * (1.0f - fractional_phase_part) +
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chaninfo->current_playback_buffer[i+1] * fractional_phase_part;
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phase += phi + phi_delta;
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}
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chaninfo->current_playback_buffer = chaninfo->speed_buffer;
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}
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playback_distance = i; // + 1;
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last_phase = (phase & fractional_part_mask);
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}
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bool
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AudioDiskstream::commit (nframes_t nframes)
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{
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