From 63bdc1a9ac18c25876dacfdcf7ad21eee5822848 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Fr=C3=A9d=C3=A9ric=20Dalleau?= Date: Mon, 8 Apr 2013 15:24:14 +0200 Subject: sbc: Add support for mSBC frame header Traditionnal SBC frame header describe encoding parameters for each frame: nr of blocks, subbands, allocation method, and bitpool. In mSBC, only one combination of parameter is defined. That combination cannot be expressed using a traditionnal SBC header. Because of this, a specific header is defined with 0xAD followed by two reserved zero bytes. --- sbc/sbc.c | 228 +++++++++++++++++++++++++++++++++++++------------------------- 1 file changed, 138 insertions(+), 90 deletions(-) diff --git a/sbc/sbc.c b/sbc/sbc.c index cea2dd1..c589217 100644 --- a/sbc/sbc.c +++ b/sbc/sbc.c @@ -379,8 +379,8 @@ static void sbc_calculate_bits(const struct sbc_frame *frame, int (*bits)[8]) * -3 CRC8 incorrect * -4 Bitpool value out of bounds */ -static int sbc_unpack_frame(const uint8_t *data, struct sbc_frame *frame, - size_t len) +static int sbc_unpack_frame_internal(const uint8_t *data, + struct sbc_frame *frame, size_t len) { unsigned int consumed; /* Will copy the parts of the header that are relevant to crc @@ -395,59 +395,6 @@ static int sbc_unpack_frame(const uint8_t *data, struct sbc_frame *frame, int bits[2][8]; /* bits distribution */ uint32_t levels[2][8]; /* levels derived from that */ - if (len < 4) - return -1; - - if (data[0] != SBC_SYNCWORD) - return -2; - - frame->frequency = (data[1] >> 6) & 0x03; - - frame->block_mode = (data[1] >> 4) & 0x03; - switch (frame->block_mode) { - case SBC_BLK_4: - frame->blocks = 4; - break; - case SBC_BLK_8: - frame->blocks = 8; - break; - case SBC_BLK_12: - frame->blocks = 12; - break; - case SBC_BLK_16: - frame->blocks = 16; - break; - } - - frame->mode = (data[1] >> 2) & 0x03; - switch (frame->mode) { - case MONO: - frame->channels = 1; - break; - case DUAL_CHANNEL: /* fall-through */ - case STEREO: - case JOINT_STEREO: - frame->channels = 2; - break; - } - - frame->allocation = (data[1] >> 1) & 0x01; - - frame->subband_mode = (data[1] & 0x01); - frame->subbands = frame->subband_mode ? 8 : 4; - - frame->bitpool = data[2]; - - if ((frame->mode == MONO || frame->mode == DUAL_CHANNEL) && - frame->bitpool > 16 * frame->subbands) - return -4; - - if ((frame->mode == STEREO || frame->mode == JOINT_STEREO) && - frame->bitpool > 32 * frame->subbands) - return -4; - - /* data[3] is crc, we're checking it later */ - consumed = 32; crc_header[0] = data[1]; @@ -548,6 +495,90 @@ static int sbc_unpack_frame(const uint8_t *data, struct sbc_frame *frame, return consumed >> 3; } +static int sbc_unpack_frame(const uint8_t *data, + struct sbc_frame *frame, size_t len) +{ + if (len < 4) + return -1; + + if (data[0] != SBC_SYNCWORD) + return -2; + + frame->frequency = (data[1] >> 6) & 0x03; + frame->block_mode = (data[1] >> 4) & 0x03; + + switch (frame->block_mode) { + case SBC_BLK_4: + frame->blocks = 4; + break; + case SBC_BLK_8: + frame->blocks = 8; + break; + case SBC_BLK_12: + frame->blocks = 12; + break; + case SBC_BLK_16: + frame->blocks = 16; + break; + } + + frame->mode = (data[1] >> 2) & 0x03; + + switch (frame->mode) { + case MONO: + frame->channels = 1; + break; + case DUAL_CHANNEL: /* fall-through */ + case STEREO: + case JOINT_STEREO: + frame->channels = 2; + break; + } + + frame->allocation = (data[1] >> 1) & 0x01; + + frame->subband_mode = (data[1] & 0x01); + frame->subbands = frame->subband_mode ? 8 : 4; + + frame->bitpool = data[2]; + + if ((frame->mode == MONO || frame->mode == DUAL_CHANNEL) && + frame->bitpool > 16 * frame->subbands) + return -4; + + if ((frame->mode == STEREO || frame->mode == JOINT_STEREO) && + frame->bitpool > 32 * frame->subbands) + return -4; + + return sbc_unpack_frame_internal(data, frame, len); +} + +static int msbc_unpack_frame(const uint8_t *data, + struct sbc_frame *frame, size_t len) +{ + if (len < 4) + return -1; + + if (data[0] != MSBC_SYNCWORD) + return -2; + if (data[1] != 0) + return -2; + if (data[2] != 0) + return -2; + + frame->frequency = SBC_FREQ_16000; + frame->block_mode = SBC_BLK_4; + frame->blocks = MSBC_BLOCKS; + frame->allocation = LOUDNESS; + frame->mode = MONO; + frame->channels = 1; + frame->subband_mode = 1; + frame->subbands = 8; + frame->bitpool = 26; + + return sbc_unpack_frame_internal(data, frame, len); +} + static void sbc_decoder_init(struct sbc_decoder_state *state, const struct sbc_frame *frame) { @@ -792,38 +823,6 @@ static SBC_ALWAYS_INLINE ssize_t sbc_pack_frame_internal(uint8_t *data, uint32_t levels[2][8]; /* levels are derived from that */ uint32_t sb_sample_delta[2][8]; - data[0] = SBC_SYNCWORD; - - data[1] = (frame->frequency & 0x03) << 6; - - data[1] |= (frame->block_mode & 0x03) << 4; - - data[1] |= (frame->mode & 0x03) << 2; - - data[1] |= (frame->allocation & 0x01) << 1; - - switch (frame_subbands) { - case 4: - /* Nothing to do */ - break; - case 8: - data[1] |= 0x01; - break; - default: - return -4; - break; - } - - data[2] = frame->bitpool; - - if ((frame->mode == MONO || frame->mode == DUAL_CHANNEL) && - frame->bitpool > frame_subbands << 4) - return -5; - - if ((frame->mode == STEREO || frame->mode == JOINT_STEREO) && - frame->bitpool > frame_subbands << 5) - return -5; - /* Can't fill in crc yet */ crc_header[0] = data[1]; @@ -891,6 +890,28 @@ static SBC_ALWAYS_INLINE ssize_t sbc_pack_frame_internal(uint8_t *data, static ssize_t sbc_pack_frame(uint8_t *data, struct sbc_frame *frame, size_t len, int joint) { + int frame_subbands = 4; + + data[0] = SBC_SYNCWORD; + + data[1] = (frame->frequency & 0x03) << 6; + data[1] |= (frame->block_mode & 0x03) << 4; + data[1] |= (frame->mode & 0x03) << 2; + data[1] |= (frame->allocation & 0x01) << 1; + + data[2] = frame->bitpool; + + if (frame->subbands != 4) + frame_subbands = 8; + + if ((frame->mode == MONO || frame->mode == DUAL_CHANNEL) && + frame->bitpool > frame_subbands << 4) + return -5; + + if ((frame->mode == STEREO || frame->mode == JOINT_STEREO) && + frame->bitpool > frame_subbands << 5) + return -5; + if (frame->subbands == 4) { if (frame->channels == 1) return sbc_pack_frame_internal( @@ -899,6 +920,7 @@ static ssize_t sbc_pack_frame(uint8_t *data, struct sbc_frame *frame, size_t len return sbc_pack_frame_internal( data, frame, len, 4, 2, joint); } else { + data[1] |= 0x01; if (frame->channels == 1) return sbc_pack_frame_internal( data, frame, len, 8, 1, joint); @@ -908,6 +930,16 @@ static ssize_t sbc_pack_frame(uint8_t *data, struct sbc_frame *frame, size_t len } } +static ssize_t msbc_pack_frame(uint8_t *data, struct sbc_frame *frame, + size_t len, int joint) +{ + data[0] = MSBC_SYNCWORD; + data[1] = 0; + data[2] = 0; + + return sbc_pack_frame_internal(data, frame, len, 8, 1, joint); +} + static void sbc_encoder_init(bool msbc, struct sbc_encoder_state *state, const struct sbc_frame *frame) { @@ -927,10 +959,24 @@ struct sbc_priv { struct SBC_ALIGNED sbc_frame frame; struct SBC_ALIGNED sbc_decoder_state dec_state; struct SBC_ALIGNED sbc_encoder_state enc_state; + int (*unpack_frame)(const uint8_t *data, struct sbc_frame *frame, + size_t len); + ssize_t (*pack_frame)(uint8_t *data, struct sbc_frame *frame, + size_t len, int joint); }; static void sbc_set_defaults(sbc_t *sbc, unsigned long flags) { + struct sbc_priv *priv = sbc->priv; + + if (priv->msbc) { + priv->pack_frame = msbc_pack_frame; + priv->unpack_frame = msbc_unpack_frame; + } else { + priv->pack_frame = sbc_pack_frame; + priv->unpack_frame = sbc_unpack_frame; + } + sbc->flags = flags; sbc->frequency = SBC_FREQ_44100; sbc->mode = SBC_MODE_STEREO; @@ -1017,7 +1063,7 @@ SBC_EXPORT ssize_t sbc_decode(sbc_t *sbc, const void *input, size_t input_len, priv = sbc->priv; - framelen = sbc_unpack_frame(input, &priv->frame, input_len); + framelen = priv->unpack_frame(input, &priv->frame, input_len); if (!priv->init) { sbc_decoder_init(&priv->dec_state, &priv->frame); @@ -1151,13 +1197,15 @@ SBC_EXPORT ssize_t sbc_encode(sbc_t *sbc, const void *input, size_t input_len, int j = priv->enc_state.sbc_calc_scalefactors_j( priv->frame.sb_sample_f, priv->frame.scale_factor, priv->frame.blocks, priv->frame.subbands); - framelen = sbc_pack_frame(output, &priv->frame, output_len, j); + framelen = priv->pack_frame(output, + &priv->frame, output_len, j); } else { priv->enc_state.sbc_calc_scalefactors( priv->frame.sb_sample_f, priv->frame.scale_factor, priv->frame.blocks, priv->frame.channels, priv->frame.subbands); - framelen = sbc_pack_frame(output, &priv->frame, output_len, 0); + framelen = priv->pack_frame(output, + &priv->frame, output_len, 0); } if (written) -- cgit v1.2.1