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Draft: VorbisDecoder, OggVorbisDecoder
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‎src/AudioTools/AudioCodecs/ContainerOgg.h‎

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#include "AudioTools/AudioCodecs/AudioCodecsBase.h"
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#include "AudioTools/AudioCodecs/CodecOpus.h"
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#include "AudioTools/CoreAudio/Buffers.h"
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#include "oggz/oggz.h"
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#include "oggz.h"
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#define OGG_READ_SIZE (1024)
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#define OGG_DEFAULT_BUFFER_SIZE (OGG_READ_SIZE)

‎src/AudioTools/AudioCodecs/OggVorbisDecoder.h‎

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#pragma once
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#include "AudioTools/AudioCodecs/AudioCodecsBase.h"
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#include "AudioTools/AudioCodecs/VorbisDecoder.h"
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#include "AudioTools/AudioCodecs/ContainerOgg.h"
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namespace audio_tools {
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/**
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* @brief Ogg Vorbis Decoder
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*
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* This class wraps VorbisDecoder in an Ogg container decoder, allowing
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* decoding of Ogg Vorbis streams with automatic packet extraction.
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*
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* Usage:
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* 1. Instantiate OggVorbisDecoder.
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* 2. Feed Ogg Vorbis data to the decoder.
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* 3. PCM output is provided via the underlying VorbisDecoder.
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*
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* @author Phil Schatzmann
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* @ingroup codecs
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* @ingroup decoder
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* @copyright GPLv3
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*/
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class OggVorbisDecoder : public OggContainerDecoder {
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public:
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/**
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* @brief Constructor for OggVorbisDecoder
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* Initializes the decoder and sets the underlying VorbisDecoder.
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*/
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OggVorbisDecoder() : OggContainerDecoder() { setDecoder(&vorbis); }
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protected:
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/** @brief Underlying Vorbis decoder */
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VorbisDecoder vorbis;
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};
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} // namespace audio_tools

‎src/AudioTools/AudioCodecs/VorbisDecoder.h‎

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#pragma once
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#include "AudioTools/AudioCodecs/AudioCodecsBase.h"
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#include "AudioTools/CoreAudio/Buffers.h"
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#include <vorbis.h>
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namespace audio_tools {
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/**
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* @brief Vorbis Audio Decoder using low-level libvorbis API
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*
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* This decoder expects Ogg Vorbis packets to be provided via the write()
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* method. It parses the Vorbis headers, initializes the decoder, and outputs
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* PCM audio.
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*
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* Usage:
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* 1. Call begin() to reset the decoder.
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* 2. Feed the first three Vorbis header packets via write().
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* 3. Feed subsequent audio packets via write().
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* 4. Use setOutput() to set the PCM output destination.
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* 5. Call audioInfo() to retrieve stream parameters after header parsing.
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*
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* @author Phil Schatzmann
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* @ingroup codecs
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* @ingroup decoder
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* @copyright GPLv3
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*/
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class VorbisDecoder : public AudioDecoder {
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public:
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/**
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* @brief Constructor for VorbisDecoder
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* @param buffer_size Size of the PCM output buffer (default: 256)
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* @param header_packets Number of Vorbis header packets (default: 3)
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*
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* Initializes the decoder and allocates the PCM output buffer.
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*/
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VorbisDecoder(size_t buffer_size = 256, int header_packets = 3)
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: pcm_buffer_size(buffer_size), num_header_packets(header_packets) {}
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/**
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* @brief Destructor for VorbisDecoder
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*
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* Cleans up all decoder resources.
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*/
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~VorbisDecoder() { end(); }
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/**
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* @brief Resets decoder state and prepares for new Vorbis stream
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*
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* This method clears all decoder state, resizes the PCM output buffer,
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* and initializes Vorbis structures. Call this before feeding header packets.
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* @return true if successful
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*/
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bool begin() override {
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end();
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pcmout_buffer.resize(pcm_buffer_size);
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vorbis_info_init(&vi);
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vorbis_comment_init(&vc);
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active = true;
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return true;
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}
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/**
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* @brief Cleans up all Vorbis decoder structures
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*/
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void end() override {
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vorbis_block_clear(&vb);
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vorbis_dsp_clear(&vd);
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vorbis_comment_clear(&vc);
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vorbis_info_clear(&vi);
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header_packets = 0;
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decoder_initialized = false;
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active = false;
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}
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/**
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* @brief Feeds a Vorbis packet (header or audio) to the decoder
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*
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* The first three packets must be Vorbis headers. Subsequent packets are
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* audio. PCM output is written to the Print stream set via setOutput().
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*
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* @param data Pointer to packet data
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* @param len Length of packet data
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* @return Number of PCM bytes written to output
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*/
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size_t write(const uint8_t *data, size_t len) override {
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ogg_packet packet;
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packet.packet = (unsigned char *)data;
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packet.bytes = len;
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packet.b_o_s = (header_packets == 0) ? 1 : 0;
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packet.e_o_s = 0;
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packet.granulepos = 0;
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packet.packetno = header_packets;
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if (num_header_packets == 0 && !decoder_initialized) {
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if (!initDecoder()) return 0;
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decoder_initialized = true;
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}
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if (header_packets < num_header_packets) {
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if (!parseHeaderPacket(packet, header_packets)) return 0;
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header_packets++;
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if (header_packets == num_header_packets) {
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if (!initDecoder()) return 0;
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decoder_initialized = true;
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}
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return 0;
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}
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if (header_packets == num_header_packets) {
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notifyAudioChange(audioInfo());
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}
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if (!decoder_initialized) return 0;
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return decodeAudioPacket(packet);
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}
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/**
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* @brief Returns audio stream info (sample rate, channels, bits per sample)
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* @return AudioInfo struct with stream parameters
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*/
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AudioInfo audioInfo() override {
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AudioInfo info;
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if (vi.channels > 0 && vi.rate > 0) {
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info.sample_rate = vi.rate;
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info.channels = vi.channels;
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info.bits_per_sample = 16;
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}
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return info;
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}
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/**
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* @brief Returns true if decoder is active
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*/
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operator bool() override { return active; }
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protected:
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/** @brief Vorbis stream info (channels, sample rate, etc.) */
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vorbis_info vi{};
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/** @brief Vorbis comment metadata */
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vorbis_comment vc{};
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/** @brief Decoder state for synthesis */
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vorbis_dsp_state vd{};
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/** @brief Block structure for synthesis */
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vorbis_block vb{};
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/** @brief Output stream for PCM audio */
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Print *p_print = nullptr;
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/** @brief Decoder active state */
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bool active = false;
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/** @brief PCM output buffer size */
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size_t pcm_buffer_size = 256;
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/** @brief Number of Vorbis header packets */
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int num_header_packets = 3;
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/** @brief Buffer for interleaved PCM output */
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Vector<int16_t> pcmout_buffer;
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int header_packets = 0;
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bool decoder_initialized = false;
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/**
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* @brief Parses a Vorbis header packet
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* @param packet Ogg Vorbis header packet
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* @param header_packets Index of header packet (0, 1, 2)
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* @return true if successful
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*/
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bool parseHeaderPacket(ogg_packet &packet, int header_packets) {
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if (vorbis_synthesis_headerin(&vi, &vc, &packet) != 0) {
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LOGE("Header packet %d invalid", header_packets);
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return false;
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}
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return true;
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}
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/**
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* @brief Initializes the Vorbis decoder after header parsing
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* @return true if successful
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*/
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bool initDecoder() {
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if (vorbis_synthesis_init(&vd, &vi) != 0) {
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LOGE("vorbis_synthesis_init failed");
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return false;
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}
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vorbis_block_init(&vd, &vb);
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return true;
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}
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/**
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* @brief Decodes an audio packet and writes PCM to output
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* @param packet Ogg Vorbis audio packet
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* @return Number of PCM bytes written
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*/
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size_t decodeAudioPacket(ogg_packet &packet) {
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size_t total_written = 0;
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if (vorbis_synthesis(&vb, &packet) == 0) {
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vorbis_synthesis_blockin(&vd, &vb);
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float **pcm = nullptr;
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int samples = vorbis_synthesis_pcmout(&vd, &pcm);
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while (samples > 0 && pcm) {
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int chunk = (samples > pcm_buffer_size) ? pcm_buffer_size : samples;
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convertFloatToInt16PCM(pcm, chunk, vi.channels);
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if (!pcmout_buffer.empty() && p_print) {
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p_print->write((uint8_t *)pcmout_buffer.data(),
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pcmout_buffer.size() * sizeof(int16_t));
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total_written += pcmout_buffer.size() * sizeof(int16_t);
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pcmout_buffer.clear();
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}
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vorbis_synthesis_read(&vd, chunk);
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samples = vorbis_synthesis_pcmout(&vd, &pcm);
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}
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}
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return total_written;
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}
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/**
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* @brief Converts float PCM to interleaved int16 PCM and stores in
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* pcmout_buffer
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* @param pcm Pointer to float PCM array [channels][samples]
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* @param samples Number of samples
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* @param channels Number of channels
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*/
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void convertFloatToInt16PCM(float **pcm, int samples, int channels) {
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for (int i = 0; i < samples; ++i) {
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for (int ch = 0; ch < channels; ++ch) {
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float val = pcm[ch][i];
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int16_t sample = (int16_t)(val * 32767.0f);
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if (sample > 32767) sample = 32767;
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if (sample < -32768) sample = -32768;
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pcmout_buffer.push_back(sample);
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}
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}
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}
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};
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} // namespace audio_tools

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