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Diffstat (limited to 'plugins/eg-sampler.lv2/peaks.h')
| -rw-r--r-- | plugins/eg-sampler.lv2/peaks.h | 270 |
1 files changed, 270 insertions, 0 deletions
diff --git a/plugins/eg-sampler.lv2/peaks.h b/plugins/eg-sampler.lv2/peaks.h new file mode 100644 index 0000000..69688b8 --- /dev/null +++ b/plugins/eg-sampler.lv2/peaks.h @@ -0,0 +1,270 @@ +/* + LV2 audio peaks utilities + Copyright 2016 David Robillard <d@drobilla.net> + + Permission to use, copy, modify, and/or distribute this software for any + purpose with or without fee is hereby granted, provided that the above + copyright notice and this permission notice appear in all copies. + + THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. +*/ + +/** + This file defines utilities for sending and receiving audio peaks for + waveform display. The functionality is divided into two objects: + PeaksSender, for sending peaks updates from the plugin, and PeaksReceiver, + for receiving such updates and caching the peaks. + + This allows peaks for a waveform of any size at any resolution to be + requested, with reasonably sized incremental updates sent over plugin ports. +*/ + +#ifndef PEAKS_H_INCLUDED +#define PEAKS_H_INCLUDED + +#include <math.h> + +#include "lv2/lv2plug.in/ns/ext/atom/forge.h" + +#define PEAKS_URI "http://lv2plug.in/ns/peaks#" +#define PEAKS__PeakUpdate PEAKS_URI "PeakUpdate" +#define PEAKS__magnitudes PEAKS_URI "magnitudes" +#define PEAKS__offset PEAKS_URI "offset" +#define PEAKS__total PEAKS_URI "total" + +#ifndef MIN +# define MIN(a, b) (((a) < (b)) ? (a) : (b)) +#endif +#ifndef MAX +# define MAX(a, b) (((a) > (b)) ? (a) : (b)) +#endif + +typedef struct { + LV2_URID atom_Float; + LV2_URID atom_Int; + LV2_URID atom_Vector; + LV2_URID peaks_PeakUpdate; + LV2_URID peaks_magnitudes; + LV2_URID peaks_offset; + LV2_URID peaks_total; +} PeaksURIs; + +typedef struct { + PeaksURIs uris; ///< URIDs used in protocol + const float* samples; ///< Sample data + uint32_t n_samples; ///< Total number of samples + uint32_t n_peaks; ///< Total number of peaks + uint32_t current_offset; ///< Current peak offset + bool sending; ///< True iff currently sending +} PeaksSender; + +typedef struct { + PeaksURIs uris; ///< URIDs used in protocol + float* peaks; ///< Received peaks, or zeroes + uint32_t n_peaks; ///< Total number of peaks +} PeaksReceiver; + +/** + Map URIs used in the peaks protocol. +*/ +static inline void +peaks_map_uris(PeaksURIs* uris, LV2_URID_Map* map) +{ + uris->atom_Float = map->map(map->handle, LV2_ATOM__Float); + uris->atom_Int = map->map(map->handle, LV2_ATOM__Int); + uris->atom_Vector = map->map(map->handle, LV2_ATOM__Vector); + uris->peaks_PeakUpdate = map->map(map->handle, PEAKS__PeakUpdate); + uris->peaks_magnitudes = map->map(map->handle, PEAKS__magnitudes); + uris->peaks_offset = map->map(map->handle, PEAKS__offset); + uris->peaks_total = map->map(map->handle, PEAKS__total); +} + +/** + Initialise peaks sender. The new sender is inactive and will do nothing + when `peaks_sender_send()` is called, until a transmission is started with + `peaks_sender_start()`. +*/ +static inline PeaksSender* +peaks_sender_init(PeaksSender* sender, LV2_URID_Map* map) +{ + memset(sender, 0, sizeof(*sender)); + peaks_map_uris(&sender->uris, map); + return sender; +} + +/** + Prepare to start a new peaks transmission. After this is called, the peaks + can be sent with successive calls to `peaks_sender_send()`. +*/ +static inline void +peaks_sender_start(PeaksSender* sender, + const float* samples, + uint32_t n_samples, + uint32_t n_peaks) +{ + sender->samples = samples; + sender->n_samples = n_samples; + sender->n_peaks = n_peaks; + sender->current_offset = 0; + sender->sending = true; +} + +/** + Forge a message which sends a range of peaks. Writes a peaks:PeakUpdate + object to `forge`, like: + + [source,n3] + ---- + [] + a peaks:PeakUpdate ; + peaks:offset 256 ; + peaks:total 1024 ; + peaks:magnitudes [ 0.2f, 0.3f, ... ] . + ---- +*/ +static inline bool +peaks_sender_send(PeaksSender* sender, + LV2_Atom_Forge* forge, + uint32_t n_frames, + uint32_t offset) +{ + const PeaksURIs* uris = &sender->uris; + if (!sender->sending || sender->current_offset >= sender->n_peaks) { + return sender->sending = false; + } + + // Start PeakUpdate object + lv2_atom_forge_frame_time(forge, offset); + LV2_Atom_Forge_Frame frame; + lv2_atom_forge_object(forge, &frame, 0, uris->peaks_PeakUpdate); + + // eg:offset = OFFSET + lv2_atom_forge_key(forge, uris->peaks_offset); + lv2_atom_forge_int(forge, sender->current_offset); + + // eg:total = TOTAL + lv2_atom_forge_key(forge, uris->peaks_total); + lv2_atom_forge_int(forge, sender->n_peaks); + + // eg:magnitudes = Vector<Float>(PEAK, PEAK, ...) + lv2_atom_forge_key(forge, uris->peaks_magnitudes); + LV2_Atom_Forge_Frame vec_frame; + lv2_atom_forge_vector_head( + forge, &vec_frame, sizeof(float), uris->atom_Float); + + // Calculate how many peaks to send this update + const int chunk_size = MAX(1, sender->n_samples / sender->n_peaks); + const uint32_t space = forge->size - forge->offset; + const uint32_t remaining = sender->n_peaks - sender->current_offset; + const int n_update = MIN(remaining, + MIN(n_frames / 4, space / sizeof(float))); + + // Calculate peak (maximum magnitude) for each chunk + for (int i = 0; i < n_update; ++i) { + const int start = (sender->current_offset + i) * chunk_size; + float peak = 0.0f; + for (int j = 0; j < chunk_size; ++j) { + peak = fmaxf(peak, fabsf(sender->samples[start + j])); + } + lv2_atom_forge_float(forge, peak); + } + + // Finish message + lv2_atom_forge_pop(forge, &vec_frame); + lv2_atom_forge_pop(forge, &frame); + + sender->current_offset += n_update; + return true; +} + +/** + Initialise a peaks receiver. The receiver stores an array of all peaks, + which is updated incrementally with peaks_receiver_receive(). +*/ +static inline PeaksReceiver* +peaks_receiver_init(PeaksReceiver* receiver, LV2_URID_Map* map) +{ + memset(receiver, 0, sizeof(*receiver)); + peaks_map_uris(&receiver->uris, map); + return receiver; +} + +/** + Clear stored peaks and free all memory. This should be called when the + peaks are to be updated with a different audio source. +*/ +static inline void +peaks_receiver_clear(PeaksReceiver* receiver) +{ + free(receiver->peaks); + receiver->peaks = NULL; + receiver->n_peaks = 0; +} + +/** + Handle PeakUpdate message. + + The stored peaks array is updated with the slice of peaks in `update`, + resizing if necessary while preserving contents. + + Returns 0 if peaks have been updated, negative on error. +*/ +static inline int +peaks_receiver_receive(PeaksReceiver* receiver, const LV2_Atom_Object* update) +{ + const PeaksURIs* uris = &receiver->uris; + + // Get properties of interest from update + const LV2_Atom_Int* offset = NULL; + const LV2_Atom_Int* total = NULL; + const LV2_Atom_Vector* peaks = NULL; + lv2_atom_object_get_typed(update, + uris->peaks_offset, &offset, uris->atom_Int, + uris->peaks_total, &total, uris->atom_Int, + uris->peaks_magnitudes, &peaks, uris->atom_Vector, + 0); + + if (!offset || !total || !peaks || + peaks->body.child_type != uris->atom_Float) { + return -1; // Invalid update + } + + const uint32_t n = (uint32_t)total->body; + if (receiver->n_peaks != n) { + // Update is for a different total number of peaks, resize + receiver->peaks = (float*)realloc(receiver->peaks, n * sizeof(float)); + if (receiver->n_peaks > 0 && receiver->n_peaks < n) { + /* The peaks array is being expanded. Copy the old peaks, + duplicating each as necessary to fill the new peaks buffer. + This preserves the current peaks so that the peaks array can be + reasonably drawn at any time, but the resolution will increase + as new updates arrive. */ + const int n_per = n / receiver->n_peaks; + for (int i = n - 1; i >= 0; --i) { + receiver->peaks[i] = receiver->peaks[i / n_per]; + } + } else if (receiver->n_peaks > 0) { + /* The peak array is being shrunk. Similar to the above. */ + const int n_per = receiver->n_peaks / n; + for (int i = n - 1; i >= 0; --i) { + receiver->peaks[i] = receiver->peaks[i * n_per]; + } + } + receiver->n_peaks = n; + } + + // Copy vector contents to corresponding range in peaks array + memcpy(receiver->peaks + offset->body, + peaks + 1, + peaks->atom.size - sizeof(LV2_Atom_Vector_Body)); + + return 0; +} + +#endif // PEAKS_H_INCLUDED |