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Diffstat (limited to '')
-rw-r--r-- | src/decoder/plugins/FaadDecoderPlugin.cxx | 463 |
1 files changed, 463 insertions, 0 deletions
diff --git a/src/decoder/plugins/FaadDecoderPlugin.cxx b/src/decoder/plugins/FaadDecoderPlugin.cxx new file mode 100644 index 000000000..d59309a3a --- /dev/null +++ b/src/decoder/plugins/FaadDecoderPlugin.cxx @@ -0,0 +1,463 @@ +/* + * Copyright (C) 2003-2014 The Music Player Daemon Project + * http://www.musicpd.org + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include "config.h" +#include "FaadDecoderPlugin.hxx" +#include "../DecoderAPI.hxx" +#include "../DecoderBuffer.hxx" +#include "input/InputStream.hxx" +#include "CheckAudioFormat.hxx" +#include "tag/TagHandler.hxx" +#include "util/ConstBuffer.hxx" +#include "util/Error.hxx" +#include "util/Domain.hxx" +#include "Log.hxx" + +#include <neaacdec.h> + +#include <assert.h> +#include <string.h> +#include <unistd.h> + +static const unsigned adts_sample_rates[] = + { 96000, 88200, 64000, 48000, 44100, 32000, 24000, 22050, + 16000, 12000, 11025, 8000, 7350, 0, 0, 0 +}; + +static constexpr Domain faad_decoder_domain("faad_decoder"); + +/** + * Check whether the buffer head is an AAC frame, and return the frame + * length. Returns 0 if it is not a frame. + */ +static size_t +adts_check_frame(const unsigned char *data) +{ + /* check syncword */ + if (!((data[0] == 0xFF) && ((data[1] & 0xF6) == 0xF0))) + return 0; + + return (((unsigned int)data[3] & 0x3) << 11) | + (((unsigned int)data[4]) << 3) | + (data[5] >> 5); +} + +/** + * Find the next AAC frame in the buffer. Returns 0 if no frame is + * found or if not enough data is available. + */ +static size_t +adts_find_frame(DecoderBuffer *buffer) +{ + while (true) { + auto data = ConstBuffer<uint8_t>::FromVoid(decoder_buffer_need(buffer, 8)); + if (data.IsNull()) + /* failed */ + return 0; + + /* find the 0xff marker */ + const uint8_t *p = (const uint8_t *) + memchr(data.data, 0xff, data.size); + if (p == nullptr) { + /* no marker - discard the buffer */ + decoder_buffer_clear(buffer); + continue; + } + + if (p > data.data) { + /* discard data before 0xff */ + decoder_buffer_consume(buffer, p - data.data); + continue; + } + + /* is it a frame? */ + const size_t frame_length = adts_check_frame(data.data); + if (frame_length == 0) { + /* it's just some random 0xff byte; discard it + and continue searching */ + decoder_buffer_consume(buffer, 1); + continue; + } + + if (decoder_buffer_need(buffer, frame_length).IsNull()) { + /* not enough data; discard this frame to + prevent a possible buffer overflow */ + decoder_buffer_clear(buffer); + continue; + } + + /* found a full frame! */ + return frame_length; + } +} + +static SignedSongTime +adts_song_duration(DecoderBuffer *buffer) +{ + const InputStream &is = decoder_buffer_get_stream(buffer); + const bool estimate = !is.CheapSeeking(); + if (estimate && !is.KnownSize()) + return SignedSongTime::Negative(); + + unsigned sample_rate = 0; + + /* Read all frames to ensure correct time and bitrate */ + unsigned frames = 0; + for (;; frames++) { + const unsigned frame_length = adts_find_frame(buffer); + if (frame_length == 0) + break; + + if (frames == 0) { + auto data = ConstBuffer<uint8_t>::FromVoid(decoder_buffer_read(buffer)); + assert(!data.IsEmpty()); + assert(frame_length <= data.size); + + sample_rate = adts_sample_rates[(data.data[2] & 0x3c) >> 2]; + if (sample_rate == 0) + break; + } + + decoder_buffer_consume(buffer, frame_length); + + if (estimate && frames == 128) { + /* if this is a remote file, don't slurp the + whole file just for checking the song + duration; instead, stop after some time and + extrapolate the song duration from what we + have until now */ + + const auto offset = is.GetOffset() + - decoder_buffer_available(buffer); + if (offset <= 0) + return SignedSongTime::Negative(); + + const auto file_size = is.GetSize(); + frames = (frames * file_size) / offset; + break; + } + } + + if (sample_rate == 0) + return SignedSongTime::Negative(); + + return SignedSongTime::FromScale<uint64_t>(frames * uint64_t(1024), + sample_rate); +} + +static SignedSongTime +faad_song_duration(DecoderBuffer *buffer, InputStream &is) +{ + auto data = ConstBuffer<uint8_t>::FromVoid(decoder_buffer_need(buffer, 5)); + if (data.IsNull()) + return SignedSongTime::Negative(); + + size_t tagsize = 0; + if (data.size >= 10 && !memcmp(data.data, "ID3", 3)) { + /* skip the ID3 tag */ + + tagsize = (data.data[6] << 21) | (data.data[7] << 14) | + (data.data[8] << 7) | (data.data[9] << 0); + + tagsize += 10; + + if (!decoder_buffer_skip(buffer, tagsize)) + return SignedSongTime::Negative(); + + data = ConstBuffer<uint8_t>::FromVoid(decoder_buffer_need(buffer, 5)); + if (data.IsNull()) + return SignedSongTime::Negative(); + } + + if (data.size >= 8 && adts_check_frame(data.data) > 0) { + /* obtain the duration from the ADTS header */ + + if (!is.IsSeekable()) + return SignedSongTime::Negative(); + + auto song_length = adts_song_duration(buffer); + + is.LockSeek(tagsize, IgnoreError()); + + decoder_buffer_clear(buffer); + + return song_length; + } else if (data.size >= 5 && memcmp(data.data, "ADIF", 4) == 0) { + /* obtain the duration from the ADIF header */ + + if (!is.KnownSize()) + return SignedSongTime::Negative(); + + size_t skip_size = (data.data[4] & 0x80) ? 9 : 0; + + if (8 + skip_size > data.size) + /* not enough data yet; skip parsing this + header */ + return SignedSongTime::Negative(); + + unsigned bit_rate = ((data.data[4 + skip_size] & 0x0F) << 19) | + (data.data[5 + skip_size] << 11) | + (data.data[6 + skip_size] << 3) | + (data.data[7 + skip_size] & 0xE0); + + const auto size = is.GetSize(); + if (bit_rate == 0) + return SignedSongTime::Negative(); + + return SongTime::FromScale(size, bit_rate / 8); + } else + return SignedSongTime::Negative(); +} + +static NeAACDecHandle +faad_decoder_new() +{ + const NeAACDecHandle decoder = NeAACDecOpen(); + + NeAACDecConfigurationPtr config = + NeAACDecGetCurrentConfiguration(decoder); + config->outputFormat = FAAD_FMT_16BIT; + config->downMatrix = 1; + config->dontUpSampleImplicitSBR = 0; + NeAACDecSetConfiguration(decoder, config); + + return decoder; +} + +/** + * Wrapper for NeAACDecInit() which works around some API + * inconsistencies in libfaad. + */ +static bool +faad_decoder_init(NeAACDecHandle decoder, DecoderBuffer *buffer, + AudioFormat &audio_format, Error &error) +{ + auto data = ConstBuffer<uint8_t>::FromVoid(decoder_buffer_read(buffer)); + if (data.IsEmpty()) { + error.Set(faad_decoder_domain, "Empty file"); + return false; + } + + uint8_t channels; + uint32_t sample_rate; +#ifdef HAVE_FAAD_LONG + /* neaacdec.h declares all arguments as "unsigned long", but + internally expects uint32_t pointers. To avoid gcc + warnings, use this workaround. */ + unsigned long *sample_rate_p = (unsigned long *)(void *)&sample_rate; +#else + uint32_t *sample_rate_p = &sample_rate; +#endif + long nbytes = NeAACDecInit(decoder, + /* deconst hack, libfaad requires this */ + const_cast<unsigned char *>(data.data), + data.size, + sample_rate_p, &channels); + if (nbytes < 0) { + error.Set(faad_decoder_domain, "Not an AAC stream"); + return false; + } + + decoder_buffer_consume(buffer, nbytes); + + return audio_format_init_checked(audio_format, sample_rate, + SampleFormat::S16, channels, error); +} + +/** + * Wrapper for NeAACDecDecode() which works around some API + * inconsistencies in libfaad. + */ +static const void * +faad_decoder_decode(NeAACDecHandle decoder, DecoderBuffer *buffer, + NeAACDecFrameInfo *frame_info) +{ + auto data = ConstBuffer<uint8_t>::FromVoid(decoder_buffer_read(buffer)); + if (data.IsEmpty()) + return nullptr; + + return NeAACDecDecode(decoder, frame_info, + /* deconst hack, libfaad requires this */ + const_cast<uint8_t *>(data.data), + data.size); +} + +/** + * Determine a song file's total playing time. + * + * The first return value specifies whether the file was recognized. + * The second return value is the duration. + */ +static std::pair<bool, SignedSongTime> +faad_get_file_time(InputStream &is) +{ + DecoderBuffer *buffer = + decoder_buffer_new(nullptr, is, + FAAD_MIN_STREAMSIZE * MAX_CHANNELS); + auto duration = faad_song_duration(buffer, is); + bool recognized = !duration.IsNegative(); + + if (!recognized) { + NeAACDecHandle decoder = faad_decoder_new(); + + decoder_buffer_fill(buffer); + + AudioFormat audio_format; + if (faad_decoder_init(decoder, buffer, audio_format, + IgnoreError())) + recognized = true; + + NeAACDecClose(decoder); + } + + decoder_buffer_free(buffer); + + return std::make_pair(recognized, duration); +} + +static void +faad_stream_decode(Decoder &mpd_decoder, InputStream &is, + DecoderBuffer *buffer, const NeAACDecHandle decoder) +{ + const auto total_time = faad_song_duration(buffer, is); + + if (adts_find_frame(buffer) == 0) + return; + + /* initialize it */ + + Error error; + AudioFormat audio_format; + if (!faad_decoder_init(decoder, buffer, audio_format, error)) { + LogError(error); + return; + } + + /* initialize the MPD core */ + + decoder_initialized(mpd_decoder, audio_format, false, total_time); + + /* the decoder loop */ + + DecoderCommand cmd; + unsigned bit_rate = 0; + do { + /* find the next frame */ + + const size_t frame_size = adts_find_frame(buffer); + if (frame_size == 0) + /* end of file */ + break; + + /* decode it */ + + NeAACDecFrameInfo frame_info; + const void *const decoded = + faad_decoder_decode(decoder, buffer, &frame_info); + + if (frame_info.error > 0) { + FormatWarning(faad_decoder_domain, + "error decoding AAC stream: %s", + NeAACDecGetErrorMessage(frame_info.error)); + break; + } + + if (frame_info.channels != audio_format.channels) { + FormatDefault(faad_decoder_domain, + "channel count changed from %u to %u", + audio_format.channels, frame_info.channels); + break; + } + + if (frame_info.samplerate != audio_format.sample_rate) { + FormatDefault(faad_decoder_domain, + "sample rate changed from %u to %lu", + audio_format.sample_rate, + (unsigned long)frame_info.samplerate); + break; + } + + decoder_buffer_consume(buffer, frame_info.bytesconsumed); + + /* update bit rate and position */ + + if (frame_info.samples > 0) { + bit_rate = frame_info.bytesconsumed * 8.0 * + frame_info.channels * audio_format.sample_rate / + frame_info.samples / 1000 + 0.5; + } + + /* send PCM samples to MPD */ + + cmd = decoder_data(mpd_decoder, is, decoded, + (size_t)frame_info.samples * 2, + bit_rate); + } while (cmd != DecoderCommand::STOP); +} + +static void +faad_stream_decode(Decoder &mpd_decoder, InputStream &is) +{ + DecoderBuffer *buffer = + decoder_buffer_new(&mpd_decoder, is, + FAAD_MIN_STREAMSIZE * MAX_CHANNELS); + + /* create the libfaad decoder */ + + const NeAACDecHandle decoder = faad_decoder_new(); + + faad_stream_decode(mpd_decoder, is, buffer, decoder); + + /* cleanup */ + + NeAACDecClose(decoder); + decoder_buffer_free(buffer); +} + +static bool +faad_scan_stream(InputStream &is, + const struct tag_handler *handler, void *handler_ctx) +{ + auto result = faad_get_file_time(is); + if (!result.first) + return false; + + if (!result.second.IsNegative()) + tag_handler_invoke_duration(handler, handler_ctx, + SongTime(result.second)); + return true; +} + +static const char *const faad_suffixes[] = { "aac", nullptr }; +static const char *const faad_mime_types[] = { + "audio/aac", "audio/aacp", nullptr +}; + +const DecoderPlugin faad_decoder_plugin = { + "faad", + nullptr, + nullptr, + faad_stream_decode, + nullptr, + nullptr, + faad_scan_stream, + nullptr, + faad_suffixes, + faad_mime_types, +}; |