AudioWaveformer.cpp

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// Copyright (c) 2008-2022 OpenShot Studios, LLC
//
// SPDX-License-Identifier: LGPL-3.0-or-later
 
#include "AudioWaveformer.h"
 
#include <cmath>
 
#include <algorithm>
#include <chrono>
#include <memory>
#include <thread>
#include <vector>
 
#include "Clip.h"
#include "Exceptions.h"
#include "FrameMapper.h"
#include "FFmpegReader.h"
#include "Timeline.h"
 
 
using namespace std;
using namespace openshot;
 
 
// Default constructor
AudioWaveformer::AudioWaveformer(ReaderBase* new_reader) :
    reader(new_reader),
    detached_reader(nullptr),
    resolved_reader(nullptr),
    source_initialized(false)
{
 
}
 
// Destructor
AudioWaveformer::~AudioWaveformer()
{
 
}
 
// Extract audio samples from any ReaderBase class
AudioWaveformData AudioWaveformer::ExtractSamples(int channel, int num_per_second, bool normalize) {
    // Legacy entry point: resolve a source reader (unwrap Clip/FrameMapper), then extract audio-only.
    AudioWaveformData data;
    if (!reader) {
        return data;
    }
 
    ReaderBase* source = ResolveWaveformReader();
 
    Fraction source_fps = ResolveSourceFPS(source);
 
    AudioWaveformData base = ExtractSamplesFromReader(source, channel, num_per_second, false);
 
    // If this is a Clip, apply its keyframes using project fps (timeline if available, else reader fps)
    if (auto clip = dynamic_cast<Clip*>(reader)) {
        Timeline* timeline = dynamic_cast<Timeline*>(clip->ParentTimeline());
        Fraction project_fps = timeline ? timeline->info.fps : clip->Reader()->info.fps;
        return ApplyKeyframes(base, &clip->time, &clip->volume, project_fps, source_fps, source->info.channels, num_per_second, channel, normalize);
    }
 
    // No keyframes to apply
    if (normalize) {
        float max_sample = 0.0f;
        for (auto v : base.max_samples) {
            max_sample = std::max(max_sample, std::abs(v));
        }
        if (max_sample > 0.0f) {
            base.scale(static_cast<int>(base.max_samples.size()), 1.0f / max_sample);
        }
    }
    return base;
}
 
AudioWaveformData AudioWaveformer::ExtractSamples(const std::string& path, int channel, int num_per_second, bool normalize) {
    FFmpegReader temp_reader(path);
    temp_reader.Open();
    // Disable video for speed
    bool has_video = temp_reader.info.has_video;
    temp_reader.info.has_video = false;
    AudioWaveformData data = ExtractSamplesFromReader(&temp_reader, channel, num_per_second, normalize);
    temp_reader.info.has_video = has_video;
    temp_reader.Close();
    return data;
}
 
AudioWaveformData AudioWaveformer::ExtractSamples(const std::string& path,
                                                  const Keyframe* time_keyframe,
                                                  const Keyframe* volume_keyframe,
                                                  const Fraction& project_fps,
                                                  int channel,
                                                  int num_per_second,
                                                  bool normalize) {
    FFmpegReader temp_reader(path);
    temp_reader.Open();
    bool has_video = temp_reader.info.has_video;
    temp_reader.info.has_video = false;
    Fraction source_fps = temp_reader.info.fps;
    AudioWaveformData base = ExtractSamplesFromReader(&temp_reader, channel, num_per_second, false);
    temp_reader.info.has_video = has_video;
    temp_reader.Close();
    return ApplyKeyframes(base, time_keyframe, volume_keyframe, project_fps, source_fps, temp_reader.info.channels, num_per_second, channel, normalize);
}
 
AudioWaveformData AudioWaveformer::ApplyKeyframes(const AudioWaveformData& base,
                                                  const Keyframe* time_keyframe,
                                                  const Keyframe* volume_keyframe,
                                                  const Fraction& project_fps,
                                                  const Fraction& source_fps,
                                                  int source_channels,
                                                  int num_per_second,
                                                  int channel,
                                                  bool normalize) {
    AudioWaveformData data;
    if (num_per_second <= 0) {
        return data;
    }
 
    double project_fps_value = project_fps.ToDouble();
    double source_fps_value = source_fps.ToDouble();
    if (project_fps_value <= 0.0 || source_fps_value <= 0.0) {
        return data;
    }
 
    if (channel != -1 && (channel < 0 || channel >= source_channels)) {
        return data;
    }
 
    size_t base_total = base.max_samples.size();
    if (base_total == 0) {
        return data;
    }
 
    // Determine output duration from time curve (if any). Time curves are in project-frame domain.
    int64_t output_frames = 0;
    if (time_keyframe && time_keyframe->GetCount() > 0) {
        output_frames = time_keyframe->GetLength();
    }
    if (output_frames <= 0) {
        // Default to source duration derived from base waveform length
        double source_duration = static_cast<double>(base_total) / static_cast<double>(num_per_second);
        output_frames = static_cast<int64_t>(std::llround(source_duration * project_fps_value));
    }
    double output_duration_seconds = static_cast<double>(output_frames) / project_fps_value;
    int total_samples = static_cast<int>(std::ceil(output_duration_seconds * num_per_second));
 
    if (total_samples <= 0) {
        return data;
    }
 
    data.resize(total_samples);
    data.zero(total_samples);
 
    for (int i = 0; i < total_samples; ++i) {
        double out_time = static_cast<double>(i) / static_cast<double>(num_per_second);
        // Time keyframes are defined in project-frame domain; evaluate using project frames
        double project_frame = out_time * project_fps_value;
        double mapped_project_frame = time_keyframe ? time_keyframe->GetValue(project_frame) : project_frame;
        // Convert mapped project frame to seconds (project FPS), then to waveform index
        double source_time = mapped_project_frame / project_fps_value;
        double source_index = source_time * static_cast<double>(num_per_second);
 
        // Sample base waveform (nearest with simple linear blend)
        int idx0 = static_cast<int>(std::floor(source_index));
        int idx1 = idx0 + 1;
        double frac = source_index - static_cast<double>(idx0);
 
        float max_sample = 0.0f;
        float rms_sample = 0.0f;
        if (idx0 >= 0 && idx0 < static_cast<int>(base_total)) {
            max_sample = base.max_samples[idx0];
            rms_sample = base.rms_samples[idx0];
        }
        if (idx1 >= 0 && idx1 < static_cast<int>(base_total)) {
            max_sample = static_cast<float>((1.0 - frac) * max_sample + frac * base.max_samples[idx1]);
            rms_sample = static_cast<float>((1.0 - frac) * rms_sample + frac * base.rms_samples[idx1]);
        }
 
        double gain = 1.0;
        if (volume_keyframe) {
            double project_frame = out_time * project_fps_value;
            gain = volume_keyframe->GetValue(project_frame);
        }
        max_sample = static_cast<float>(max_sample * gain);
        rms_sample = static_cast<float>(rms_sample * gain);
 
        data.max_samples[i] = max_sample;
        data.rms_samples[i] = rms_sample;
    }
 
    if (normalize) {
        float samples_max = 0.0f;
        for (auto v : data.max_samples) {
            samples_max = std::max(samples_max, std::abs(v));
        }
        if (samples_max > 0.0f) {
            data.scale(total_samples, 1.0f / samples_max);
        }
    }
 
    return data;
}
 
AudioWaveformData AudioWaveformer::ExtractSamplesFromReader(ReaderBase* source_reader, int channel, int num_per_second, bool normalize) {
    AudioWaveformData data;
 
    if (!source_reader || num_per_second <= 0) {
        return data;
    }
 
    // Open reader (if needed)
    if (!source_reader->IsOpen()) {
        source_reader->Open();
    }
 
    const auto retry_delay = std::chrono::milliseconds(100);
    const auto max_wait_for_open = std::chrono::milliseconds(3000);
 
    auto get_frame_with_retry = [&](int64_t frame_number) -> std::shared_ptr<openshot::Frame> {
        std::chrono::steady_clock::time_point wait_start;
        bool waiting_for_open = false;
        while (true) {
            try {
                return source_reader->GetFrame(frame_number);
            } catch (const openshot::ReaderClosed&) {
                auto now = std::chrono::steady_clock::now();
                if (!waiting_for_open) {
                    waiting_for_open = true;
                    wait_start = now;
                } else if (now - wait_start >= max_wait_for_open) {
                    throw;
                }
 
                std::this_thread::sleep_for(retry_delay);
            }
        }
    };
 
    int sample_rate = source_reader->info.sample_rate;
    if (sample_rate <= 0) {
        sample_rate = num_per_second;
    }
    int sample_divisor = sample_rate / num_per_second;
    if (sample_divisor <= 0) {
        sample_divisor = 1;
    }
 
    // Determine length of video frames (for waveform)
    int64_t reader_video_length = source_reader->info.video_length;
    if (reader_video_length < 0) {
        reader_video_length = 0;
    }
    float reader_duration = source_reader->info.duration;
    double fps_value = source_reader->info.fps.ToDouble();
    float frames_duration = 0.0f;
    if (reader_video_length > 0 && fps_value > 0.0) {
        frames_duration = static_cast<float>(reader_video_length / fps_value);
    }
    if (reader_duration <= 0.0f) {
        reader_duration = frames_duration;
    }
    if (reader_duration < 0.0f) {
        reader_duration = 0.0f;
    }
 
    if (!source_reader->info.has_audio) {
        return data;
    }
 
    int total_samples = static_cast<int>(std::ceil(reader_duration * num_per_second));
    if (total_samples <= 0 || source_reader->info.channels == 0) {
        return data;
    }
 
    if (channel != -1 && (channel < 0 || channel >= source_reader->info.channels)) {
        return data;
    }
 
    // Resize and clear audio buffers
    data.resize(total_samples);
    data.zero(total_samples);
 
    int extracted_index = 0;
    int sample_index = 0;
    float samples_max = 0.0f;
    float chunk_max = 0.0f;
    double chunk_squared_sum = 0.0;
 
    int channel_count = (channel == -1) ? source_reader->info.channels : 1;
    std::vector<float*> channels(source_reader->info.channels, nullptr);
 
    try {
        for (int64_t f = 1; f <= reader_video_length && extracted_index < total_samples; f++) {
            std::shared_ptr<openshot::Frame> frame = get_frame_with_retry(f);
 
            for (int channel_index = 0; channel_index < source_reader->info.channels; channel_index++) {
                if (channel == channel_index || channel == -1) {
                    channels[channel_index] = frame->GetAudioSamples(channel_index);
                }
            }
 
            int sample_count = frame->GetAudioSamplesCount();
            for (int s = 0; s < sample_count; s++) {
                for (int channel_index = 0; channel_index < source_reader->info.channels; channel_index++) {
                    if (channel == channel_index || channel == -1) {
                        float *samples = channels[channel_index];
                        if (!samples) {
                            continue;
                        }
                        float abs_sample = std::abs(samples[s]);
                        chunk_squared_sum += static_cast<double>(samples[s]) * static_cast<double>(samples[s]);
                        chunk_max = std::max(chunk_max, abs_sample);
                    }
                }
 
                sample_index += 1;
 
                if (sample_index % sample_divisor == 0) {
                    float avg_squared_sum = 0.0f;
                    if (channel_count > 0) {
                        avg_squared_sum = static_cast<float>(chunk_squared_sum / static_cast<double>(sample_divisor * channel_count));
                    }
 
                    if (extracted_index < total_samples) {
                        data.max_samples[extracted_index] = chunk_max;
                        data.rms_samples[extracted_index] = std::sqrt(avg_squared_sum);
                        samples_max = std::max(samples_max, chunk_max);
                        extracted_index++;
                    }
 
                    sample_index = 0;
                    chunk_max = 0.0f;
                    chunk_squared_sum = 0.0;
 
                    if (extracted_index >= total_samples) {
                        break;
                    }
                }
            }
        }
    } catch (...) {
        throw;
    }
 
    if (sample_index > 0 && extracted_index < total_samples) {
        float avg_squared_sum = 0.0f;
        if (channel_count > 0) {
            avg_squared_sum = static_cast<float>(chunk_squared_sum / static_cast<double>(sample_index * channel_count));
        }
 
        data.max_samples[extracted_index] = chunk_max;
        data.rms_samples[extracted_index] = std::sqrt(avg_squared_sum);
        samples_max = std::max(samples_max, chunk_max);
        extracted_index++;
    }
 
    if (normalize && samples_max > 0.0f) {
        float scale = 1.0f / samples_max;
        data.scale(total_samples, scale);
    }
 
    return data;
}
 
ReaderBase* AudioWaveformer::ResolveSourceReader(ReaderBase* source_reader) {
    if (!source_reader) {
        return nullptr;
    }
 
    ReaderBase* current = source_reader;
    while (true) {
        if (auto clip = dynamic_cast<Clip*>(current)) {
            current = clip->Reader();
            continue;
        }
        if (auto mapper = dynamic_cast<FrameMapper*>(current)) {
            current = mapper->Reader();
            continue;
        }
        break;
    }
    return current;
}
 
Fraction AudioWaveformer::ResolveSourceFPS(ReaderBase* source_reader) {
    if (!source_reader) {
        return Fraction(0, 1);
    }
    return source_reader->info.fps;
}
 
// Resolve and cache the reader used for waveform extraction (prefer a detached FFmpegReader clone)
ReaderBase* AudioWaveformer::ResolveWaveformReader() {
    if (source_initialized) {
        return resolved_reader ? resolved_reader : reader;
    }
    source_initialized = true;
 
    resolved_reader = ResolveSourceReader(reader);
 
    // Prefer a detached, audio-only FFmpegReader clone so we never mutate the live reader used for preview.
    if (auto ff_reader = dynamic_cast<FFmpegReader*>(resolved_reader)) {
        const Json::Value ff_json = ff_reader->JsonValue();
        const std::string path = ff_json.get("path", "").asString();
        if (!path.empty()) {
            try {
                auto clone = std::make_unique<FFmpegReader>(path, false);
                clone->SetJsonValue(ff_json);
                clone->info.has_video = false; // explicitly audio-only for waveform extraction
                detached_reader = std::move(clone);
                resolved_reader = detached_reader.get();
            } catch (...) {
                // Fall back to using the original reader if cloning fails
                detached_reader.reset();
                resolved_reader = ResolveSourceReader(reader);
            }
        }
    }
 
    return resolved_reader ? resolved_reader : reader;
}