mirror of https://github.com/mpv-player/mpv
127 lines
6.1 KiB
C
127 lines
6.1 KiB
C
// This filter was ported from Chromium
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// (https://chromium.googlesource.com/chromium/chromium/+/51ed77e3f37a9a9b80d6d0a8259e84a8ca635259/media/filters/audio_renderer_algorithm.cc)
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//
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// Copyright 2015 The Chromium Authors. All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived from
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// this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#include "common/common.h"
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struct mp_scaletempo2_opts {
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// Max/min supported playback rates for fast/slow audio. Audio outside of these
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// ranges are muted.
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// Audio at these speeds would sound better under a frequency domain algorithm.
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float min_playback_rate;
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float max_playback_rate;
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// Overlap-and-add window size in milliseconds.
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float ola_window_size_ms;
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// Size of search interval in milliseconds. The search interval is
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// [-delta delta] around |output_index| * |playback_rate|. So the search
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// interval is 2 * delta.
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float wsola_search_interval_ms;
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};
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struct mp_scaletempo2 {
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struct mp_scaletempo2_opts *opts;
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// Number of channels in audio stream.
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int channels;
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// Sample rate of audio stream.
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int samples_per_second;
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// If muted, keep track of partial frames that should have been skipped over.
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double muted_partial_frame;
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// Book keeping of the current time of generated audio, in frames.
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// Corresponds to the center of |search_block|. This is increased in
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// intervals of |ola_hop_size| multiplied by the current playback_rate,
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// for every WSOLA iteration. This tracks the number of advanced frames as
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// a double to achieve accurate playback rates beyond the integer precision
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// of |search_block_index|.
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// Needs to be adjusted like any other index when frames are evicted from
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// |input_buffer|.
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double output_time;
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// The offset of the center frame of |search_block| w.r.t. its first frame.
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int search_block_center_offset;
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// Index of the beginning of the |search_block|, in frames. This may be
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// negative, which is handled by |peek_audio_with_zero_prepend|.
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int search_block_index;
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// Number of Blocks to search to find the most similar one to the target
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// frame.
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int num_candidate_blocks;
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// Index of the beginning of the target block, counted in frames.
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int target_block_index;
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// Overlap-and-add window size in frames.
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int ola_window_size;
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// The hop size of overlap-and-add in frames. This implementation assumes 50%
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// overlap-and-add.
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int ola_hop_size;
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// Number of frames in |wsola_output| that overlap-and-add is completed for
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// them and can be copied to output if fill_buffer() is called. It also
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// specifies the index where the next WSOLA window has to overlap-and-add.
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int num_complete_frames;
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// Whether |wsola_output| contains an additional |ola_hop_size| of overlap
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// frames for the next iteration.
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bool wsola_output_started;
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// Overlap-and-add window.
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float *ola_window;
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// Transition window, used to update |optimal_block| by a weighted sum of
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// |optimal_block| and |target_block|.
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float *transition_window;
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// This stores a part of the output that is created but couldn't be rendered.
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// Output is generated frame-by-frame which at some point might exceed the
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// number of requested samples. Furthermore, due to overlap-and-add,
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// the last half-window of the output is incomplete, which is stored in this
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// buffer.
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float **wsola_output;
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int wsola_output_size;
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// Auxiliary variables to avoid allocation in every iteration.
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// Stores the optimal block in every iteration. This is the most
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// similar block to |target_block| within |search_block| and it is
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// overlap-and-added to |wsola_output|.
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float **optimal_block;
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// A block of data that search is performed over to find the |optimal_block|.
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float **search_block;
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int search_block_size;
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// Stores the target block, denoted as |target| above. |search_block| is
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// searched for a block (|optimal_block|) that is most similar to
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// |target_block|.
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float **target_block;
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// Buffered audio data.
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float **input_buffer;
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int input_buffer_size;
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int input_buffer_frames;
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float *energy_candidate_blocks;
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};
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void mp_scaletempo2_destroy(struct mp_scaletempo2 *p);
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void mp_scaletempo2_reset(struct mp_scaletempo2 *p);
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void mp_scaletempo2_init(struct mp_scaletempo2 *p, int channels, int rate);
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double mp_scaletempo2_get_latency(struct mp_scaletempo2 *p, double playback_rate);
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int mp_scaletempo2_fill_input_buffer(struct mp_scaletempo2 *p,
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uint8_t **planes, int frame_size, bool final, double playback_rate);
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int mp_scaletempo2_fill_buffer(struct mp_scaletempo2 *p,
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float **dest, int dest_size, double playback_rate);
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bool mp_scaletempo2_frames_available(struct mp_scaletempo2 *p, double playback_rate);
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