py_aax_decode/py_aax_decode/native.py

from enum import Enum
import ctypes
from ctypes import byref
import wave


class MetaData(Enum):
    album_artist = 0x40617574
    publisher = 0x4070726F
    artist = 0x406E6172
    title = 0x406C6465   # TIT3
    copyright = 0x40636F70
    date = 0x40706461
    JPEG = 0x40636172
    audible_id = 0x40706964
    album = 0x40746974
    # _unknown1 = 0x40707469
    # _unknown2 = 0x40736465 #SHORTDESC
    # _unknown3 = 0x4075616 #STILLNOKLINGON?


def main(in_file, out_file, dll_path=None):
    if dll_path is None:
        dll_path = 'C:/Program Files (x86)/Audible/Bin/AAXSDKWin.dll'

    dll = ctypes.CDLL(dll_path)
    handle = open_file(dll, in_file)

    a = (dll, handle)
    channels = get_audio_channel_count(*a)
    sample_rate = get_sample_rate(*a)
    seek(*a, 0)
    authenticate(*a)

    print('c', channels, 's', sample_rate)

    n_chapters = get_chapter_count(*a)
    chapter_times = [get_chapter_start_time(*a, i) for i in range(n_chapters)]

    with open(out_file + '.txt', 'w') as f:
        [f.write(str(ti) + '\n') for ti in chapter_times]

    enc_buf = ctypes.create_string_buffer(0x400)
    dec_buf = ctypes.create_string_buffer(0x400 * 200)

    length = 0
    with wave.open(out_file, 'wb') as wav:
        wav.setnchannels(channels)
        wav.setframerate(sample_rate)
        wav.setsampwidth(2)

        while True:
            enc_data, enc_len = get_encoded_audio(*a, enc_buf)

            if enc_len == 0:
                break

            dec_data, dec_len = decode_pcm_frame(*a, enc_buf, enc_len, dec_buf)
            length += dec_len

            wav.writeframes(bytearray(dec_buf)[:dec_len])

    close_file(*a)


def open_file(dll, filename):
    handle = ctypes.pointer(ctypes.c_byte())
    res = dll.AAXOpenFileWinW(byref(handle), filename)

    if res != 0:
        raise Exception('AAXOpenFileWinW: {}'.format(res))

    return handle


def close_file(dll, handle):
    res = dll.AAXCloseFile(handle)

    if res != 0:
        raise Exception('AAXCloseFile: {}'.format(res))


def get_audio_channel_count(dll, handle):
    n_channels = ctypes.c_uint()
    res = dll.AAXGetAudioChannelCount(handle, byref(n_channels))

    if res != 0:
        raise Exception('AAXGetAudioChannelCount: {}'.format(res))

    return n_channels.value


def get_sample_rate(dll, handle):
    sample_rate = ctypes.c_uint()
    res = dll.AAXGetSampleRate(handle, byref(sample_rate))

    if res != 0:
        raise Exception('AAXGetSampleRate: {}'.format(res))

    return sample_rate.value


def seek(dll, handle, position=0):
    res = dll.AAXSeek(handle, ctypes.c_int(position))

    if res != 0:
        raise Exception('AAXSeek: {}'.format(res))


def authenticate(dll, handle):
    res = dll.AAXAuthenticateWin(handle)

    if res != 0:
        raise Exception('AAXAuthenticateWin: {}'.format(res))


def get_encoded_audio(dll, handle, buf=None):
    if buf is None:
        buf = ctypes.create_string_buffer(0x400)

    data_len = ctypes.c_uint()
    res = dll.AAXGetEncodedAudio(handle, buf, len(buf), byref(data_len))

    if res not in (0, -24):
		#-24 is "read past end of data"
        raise Exception('AAXGetEncodedAudio: {}'.format(res))

    return buf, data_len.value


def decode_pcm_frame(dll, handle, in_buf, in_len, out_buf=None):
    if out_buf is None:
        out_buf = ctypes.create_string_buffer(0x400 * 200)

    data_len = ctypes.c_uint()
    res = dll.AAXDecodePCMFrame(handle, in_buf, in_len, out_buf, len(out_buf), byref(data_len))

    if res != 0:
        raise Exception('AAXDecodedPCMFrame: {}'.format(res))

    return out_buf, data_len.value


def get_chapter_text(dll, handle, chapter_num, buf=None):
    '''
    Possibly doesn't exist?
	'''
    if buf is None:
        buf = ctypes.create_string_buffer(0x800)

    data_len = ctypes.c_uint()
    res = dll.AAXGetChapterText(handle, ctypes.c_uint(chapter_num), buf, len(buf), byref(data_len))

    if data_len.value == 0:
        return ''

    if res != 0:
        raise Exception('AAXGetChapterText: {}'.format(res))

    return bytearray(buf[:data_len.value]).decode('utf-8')


def get_metadata(dll, handle, mdn):
    data_len = ctypes.c_uint()
    res = dll.AAXGetMetadataInfo(handle, ctypes.c_int(mdn), None, byref(data_len))

    if res != 0:
        raise Exception('AAXGetMetadataInfo: {}'.format(res))

    buf = ctypes.create_string_buffer(data_len)
    res = dll.AAXGetMetadata(handle, ctypes.int(mdn), buf, byref(data_len))

    if res != 0:
        raise Exception('AAXGetChapterText: {}'.format(res))

    return buf, data_len.value


def seek_to_chapter(dll, handle, chapter):
    res = dll.AAXSeekToChapter(handle, ctypes.c_uint(chapter))

    if res != 0:
        raise Exception('AAXSeekToChapter: {}'.format(res))


def get_chapter_count(dll, handle):
    n_chapters = ctypes.c_uint()
    res = dll.AAXGetChapterCount(handle, byref(n_chapters))

    if res != 0:
        raise Exception('AAXGetChapterCount: {}'.format(res))

    return n_chapters.value


def get_current_chapter(dll, handle):
    chapter = ctypes.c_uint()
    res = dll.AAXGetCurrentChapter(handle, byref(chapter))

    if res != 0:
        raise Exception('AAXGetCurrentChapter: {}'.format(res))

    return chapter.value


def get_duration(dll, handle):
    duration = ctypes.c_uint()
    res = dll.AAXGetDuration(handle, byref(duration))

    if res != 0:
        raise Exception('AAXGetDuration: {}'.format(res))

    return duration.value


def get_playback_position(dll, handle):
    position = ctypes.c_uint()
    res = dll.AAXGetPlaybackPosition(handle, byref(position))

    if res != 0:
        raise Exception('AAXGetPlaybackPosition: {}'.format(res))

    return position.value


def get_chapter_start_time(dll, handle, chapter):
    position = ctypes.c_uint()
    res = dll.AAXGetChapterStartTime(handle, ctypes.c_uint(chapter), byref(position))

    if res != 0:
        raise Exception('AAXGetChapterStartTime: {}'.format(res))

    return position.value


def get_avg_bitrate(dll, handle):
    bitrate = ctypes.c_uint()
    res = dll.AAXGetAvgBitrate(handle, byref(bitrate))

    if res != 0:
        raise Exception('AAXGetAvgBitrate: {}'.format(res))

    return bitrate.value


def get_max_bitrate(dll, handle):
    bitrate = ctypes.c_uint()
    res = dll.AAXGetMaxBitrate(handle, byref(bitrate))

    if res != 0:
        raise Exception('AAXGetAvgBitrate: {}'.format(res))

    return bitrate.value