CodecCodec2.h

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#pragma once
 
#include "AudioTools/AudioCodecs/AudioCodecsBase.h"
#include "codec2.h"
 
 
namespace audio_tools {

int getCodec2Mode(int bits_per_second) {
  switch (bits_per_second) {
    case 3200:
      return CODEC2_MODE_3200;
    case 2400:
      return CODEC2_MODE_2400;
    case 1600:
      return CODEC2_MODE_1600;
    case 1400:
      return CODEC2_MODE_1400;
    case 1300:
      return CODEC2_MODE_1300;
    case 1200:
      return CODEC2_MODE_1200;
    case 700:
      return CODEC2_MODE_700C;
    case 450:
      return CODEC2_MODE_450;
    default:
      LOGE(
          "Unsupported sample rate: use 3200, 2400, 1600, 1400, 1300, 1200, "
          "700 or 450");
      return -1;
  }
}

class Codec2Decoder : public AudioDecoder {
 public:
  Codec2Decoder(int bps = 3200) {
    info.sample_rate = 8000;
    info.channels = 1;
    info.bits_per_sample = 16;
    setBitsPerSecond(bps);
  }
 
  virtual const char *mime() override { return "audio/codec2"; }

  virtual void setBitsPerSecond(int bps) { bits_per_second = bps; }
 
  int bitsPerSecond() { return bits_per_second; }
 
  virtual bool begin() {
    TRACEI();
 
    int mode = getCodec2Mode(bits_per_second);
    if (mode == -1) {
      LOGE("invalid bits_per_second")
      return false;
    }
    if (info.channels != 1) {
      LOGE("Only 1 channel supported")
      return false;
    }
    if (info.bits_per_sample != 16) {
      LOGE("Only 16 bps are supported")
      return false;
    }
    if (info.sample_rate != 8000) {
      LOGW("Sample rate should be 8000: %d", info.sample_rate);
    }
 
    p_codec2 = codec2_create(mode);
    if (p_codec2 == nullptr) {
      LOGE("codec2_create");
      return false;
    }
 
    result_buffer.resize(bytesCompressed());
    input_buffer.resize(bytesCompressed() );
 
    assert(input_buffer.size()>0);
    assert(result_buffer.size()>0);
 
    notifyAudioChange(info);
    LOGI("bytesCompressed:%d", bytesCompressed());
    LOGI("bytesUncompressed:%d", bytesUncompressed());
    is_active = true;
    return true;
  }
 
  int bytesCompressed() {
    return p_codec2 != nullptr ? codec2_bytes_per_frame(p_codec2) : 0;
  }
 
  int bytesUncompressed() {
    return p_codec2 != nullptr
               ? codec2_samples_per_frame(p_codec2) * sizeof(int16_t)
               : 0;
  }
 
 
  virtual void end() {
    TRACEI();
    codec2_destroy(p_codec2);
    is_active = false;
  }
 
  virtual void setOutput(Print &out_stream) { p_print = &out_stream; }
 
  operator bool() { return is_active; }
 
  size_t write(const uint8_t *data, size_t len) override {
    LOGD("write: %d", len);
    if (!is_active) {
      LOGE("inactive");
      return 0;
    }
 
    uint8_t *p_byte = (uint8_t *)data;
    for (int j = 0; j < len; j++) {
      processByte(p_byte[j]);
    }
 
    return len;
  }
 
 protected:
  Print *p_print = nullptr;
  struct CODEC2 *p_codec2;
  bool is_active = false;
  Vector<uint8_t> input_buffer;
  Vector<uint8_t> result_buffer;
  int input_pos = 0;
  int bits_per_second = 0;

  void processByte(uint8_t byte) {
    // add byte to buffer
    input_buffer[input_pos++] = byte;
 
    // decode if buffer is full
    if (input_pos >= input_buffer.size()) {
      codec2_decode(p_codec2, (short*)result_buffer.data(), input_buffer.data());
      int written = p_print->write((uint8_t *)result_buffer.data(), result_buffer.size());
      if (written != result_buffer.size()){
        LOGE("write: %d written: %d", result_buffer.size(), written);
      } else {
        LOGD("write: %d written: %d", result_buffer.size(), written);
      }
      delay(2);
      input_pos = 0;
    }
  }
};

class Codec2Encoder : public AudioEncoder {
 public:
  Codec2Encoder(int bps = 3200) {
    info.sample_rate = 8000;
    info.channels = 1;
    info.bits_per_sample = 16;
    setBitsPerSecond(bps);
  }

  virtual void setBitsPerSecond(int bps) { bits_per_second = bps; }
 
  int bitsPerSecond() { return bits_per_second; }
 
  int bytesCompressed() {
    return p_codec2 != nullptr ? codec2_bytes_per_frame(p_codec2) : 0;
  }
 
  int bytesUncompressed() {
    return p_codec2 != nullptr
               ? codec2_samples_per_frame(p_codec2) * sizeof(int16_t)
               : 0;
  }
 
  bool begin() {
    TRACEI();
 
    int mode = getCodec2Mode(bits_per_second);
    if (mode == -1) {
      LOGE("invalid bits_per_second")
      return false;
    }
    if (info.channels != 1) {
      LOGE("Only 1 channel supported")
      return false;
    }
    if (info.bits_per_sample != 16) {
      LOGE("Only 16 bps are supported")
      return false;
    }
    if (info.sample_rate != 8000) {
      LOGW("Sample rate should be 8000: %d", info.sample_rate);
    }
 
    p_codec2 = codec2_create(mode);
    if (p_codec2 == nullptr) {
      LOGE("codec2_create");
      return false;
    }
 
    input_buffer.resize(bytesCompressed());
    result_buffer.resize(bytesUncompressed());
    assert(input_buffer.size()>0);
    assert(result_buffer.size()>0);
    LOGI("bytesCompressed:%d", bytesCompressed());
    LOGI("bytesUncompressed:%d", bytesUncompressed());
    is_active = true;
    return true;
  }
 
  virtual void end() {
    TRACEI();
    codec2_destroy(p_codec2);
    is_active = false;
  }
 
  virtual const char *mime() { return "audio/codec2"; }
 
  virtual void setOutput(Print &out_stream) { p_print = &out_stream; }
 
  operator bool() { return is_active; }
 
  size_t write(const uint8_t *in_ptr, size_t in_size) override {
    LOGD("write: %d", in_size);
    if (!is_active) {
      LOGE("inactive");
      return 0;
    }
    // encode bytes
    uint8_t *p_byte = (uint8_t *)in_ptr;
    for (int j = 0; j < in_size; j++) {
      processByte(p_byte[j]);
    }
    return in_size;
  }
 
 protected:
  Print *p_print = nullptr;
  struct CODEC2 *p_codec2 = nullptr;
  bool is_active = false;
  int buffer_pos = 0;
  Vector<uint8_t> input_buffer;
  Vector<uint8_t> result_buffer;
  int bits_per_second = 0;
 
  // add byte to decoding buffer and decode if buffer is full
  void processByte(uint8_t byte) {
    input_buffer[buffer_pos++] = byte;
    if (buffer_pos >= input_buffer.size()) {
      // encode
      codec2_encode(p_codec2, result_buffer.data(),
                    (short*)input_buffer.data());
      int written = p_print->write(result_buffer.data(), result_buffer.size());
      if(written!=result_buffer.size()){
        LOGE("write: %d written: %d", result_buffer.size(), written);
      } else {
        LOGD("write: %d written: %d", result_buffer.size(), written);
      }
      buffer_pos = 0;
    }
  }
};
 
}  // namespace audio_tools