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/*
* Copyright 2023 jacqueline <me@jacqueline.id.au>
*
* SPDX-License-Identifier: GPL-3.0-only
*/
#include "audio/audio_decoder.hpp"
#include <cassert>
#include <cmath>
#include <cstddef>
#include <cstdint>
#include <cstdlib>
#include <cstring>
#include <deque>
#include <memory>
#include <span>
#include <variant>
#include "esp_err.h"
#include "esp_heap_caps.h"
#include "esp_log.h"
#include "freertos/portmacro.h"
#include "freertos/projdefs.h"
#include "freertos/queue.h"
#include "audio/audio_events.hpp"
#include "audio/audio_fsm.hpp"
#include "audio/audio_sink.hpp"
#include "audio/audio_source.hpp"
#include "audio/processor.hpp"
#include "codec.hpp"
#include "database/track.hpp"
#include "drivers/i2s_dac.hpp"
#include "events/event_queue.hpp"
#include "sample.hpp"
#include "tasks.hpp"
#include "types.hpp"
#include "ui/ui_fsm.hpp"
namespace audio {
static const char* kTag = "decoder";
/*
* The size of the buffer used for holding decoded samples. This buffer is
* allocated in internal memory for greater speed, so be careful when
* increasing its size.
*/
static constexpr std::size_t kCodecBufferLength =
drivers::kI2SBufferLengthFrames * 2;
auto Decoder::Start(std::shared_ptr<SampleProcessor> sink) -> Decoder* {
Decoder* task = new Decoder(sink);
tasks::StartPersistent<tasks::Type::kAudioDecoder>([=]() { task->Main(); });
return task;
}
auto Decoder::open(std::shared_ptr<TaggedStream> stream) -> void {
NextStream* next = new NextStream();
next->stream = stream;
// The decoder services its queue very quickly, so blocking on this write
// should be fine. If we discover contention here, then adding more space for
// items to next_stream_ should be fine too.
xQueueSend(next_stream_, &next, portMAX_DELAY);
}
Decoder::Decoder(std::shared_ptr<SampleProcessor> processor)
: processor_(processor), next_stream_(xQueueCreate(1, sizeof(void*))) {
ESP_LOGI(kTag, "allocating codec buffer, %u KiB", kCodecBufferLength / 1024);
codec_buffer_ = {
reinterpret_cast<sample::Sample*>(heap_caps_calloc(
kCodecBufferLength, sizeof(sample::Sample), MALLOC_CAP_DMA)),
kCodecBufferLength};
}
/*
* Main decoding loop. Handles watching for new streams, or continuing to nudge
* along the current stream if we have one.
*/
IRAM_ATTR
void Decoder::Main() {
for (;;) {
// How long should we spend waiting for a command? By default, assume we're
// idle and wait forever.
TickType_t wait_time = portMAX_DELAY;
if (!leftover_samples_.empty() || stream_) {
// If we have work to do, then don't block waiting for a new stream.
wait_time = 0;
}
NextStream* next;
if (xQueueReceive(next_stream_, &next, wait_time)) {
// Copy the data out of the queue, then clean up the item.
std::shared_ptr<TaggedStream> new_stream = next->stream;
delete next;
// If we were already decoding, then make sure we finish up the current
// file gracefully.
if (stream_) {
finishDecode(true);
}
// Ensure there's actually stream data; we might have been given nullptr
// as a signal to stop.
if (!new_stream) {
continue;
}
// Start decoding the new stream.
prepareDecode(new_stream);
// Keep handling commands until the command queue is empty.
continue;
}
// We should always have a stream if we returned from xQueueReceive without
// receiving a new stream.
assert(stream_);
if (!continueDecode()) {
finishDecode(false);
}
}
}
auto Decoder::prepareDecode(std::shared_ptr<TaggedStream> stream) -> void {
auto stub_track = std::make_shared<TrackInfo>(TrackInfo{
.tags = stream->tags(),
.uri = stream->Filepath(),
.duration = {},
.start_offset = {},
.bitrate_kbps = {},
.encoding = stream->type(),
.format = {},
});
codec_.reset(codecs::CreateCodecForType(stream->type()).value_or(nullptr));
if (!codec_) {
ESP_LOGE(kTag, "no codec found for stream");
events::Audio().Dispatch(
internal::DecodingFailedToStart{.track = stub_track});
return;
}
auto open_res = codec_->OpenStream(stream, stream->Offset());
if (open_res.has_error()) {
ESP_LOGE(kTag, "codec failed to start: %s",
codecs::ICodec::ErrorString(open_res.error()).c_str());
events::Audio().Dispatch(
internal::DecodingFailedToStart{.track = stub_track});
return;
}
// Decoding started okay! Fill out the rest of the track info for this
// stream.
stream_ = stream;
track_ = std::make_shared<TrackInfo>(TrackInfo{
.tags = stream->tags(),
.uri = stream->Filepath(),
.duration = {},
.start_offset = stream->Offset(),
.bitrate_kbps = {},
.encoding = stream->type(),
.format =
{
.sample_rate = open_res->sample_rate_hz,
.num_channels = open_res->num_channels,
.bits_per_sample = 16,
},
});
if (open_res->total_samples) {
track_->duration = open_res->total_samples.value() /
open_res->num_channels / open_res->sample_rate_hz;
}
events::Audio().Dispatch(internal::DecodingStarted{.track = track_});
processor_->beginStream(track_);
}
auto Decoder::continueDecode() -> bool {
// First, see if we have any samples from a previous decode that still need
// to be sent.
if (!leftover_samples_.empty()) {
leftover_samples_ = processor_->continueStream(leftover_samples_);
return true;
}
// We might have already cleaned up the codec if the last decode pass of the
// stream resulted in leftover samples.
if (!codec_) {
return false;
}
auto res = codec_->DecodeTo(codec_buffer_);
if (res.has_error()) {
return false;
}
if (res->samples_written > 0) {
leftover_samples_ =
processor_->continueStream(codec_buffer_.first(res->samples_written));
}
if (res->is_stream_finished) {
// The codec has finished, so make sure we don't call it again.
codec_.reset();
}
// We're done iff the codec has finished and we sent everything.
return codec_ || !leftover_samples_.empty();
}
auto Decoder::finishDecode(bool cancel) -> void {
assert(track_);
// Tell everyone we're finished.
if (cancel) {
events::Audio().Dispatch(internal::DecodingCancelled{.track = track_});
} else {
events::Audio().Dispatch(internal::DecodingFinished{.track = track_});
}
processor_->endStream(cancel);
// Clean up after ourselves.
leftover_samples_ = {};
stream_.reset();
codec_.reset();
track_.reset();
}
} // namespace audio
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