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Diffstat (limited to 'stack/a2dp/a2d_sbc.c')
| -rw-r--r-- | stack/a2dp/a2d_sbc.c | 386 |
1 files changed, 386 insertions, 0 deletions
diff --git a/stack/a2dp/a2d_sbc.c b/stack/a2dp/a2d_sbc.c new file mode 100644 index 0000000..cec335a --- /dev/null +++ b/stack/a2dp/a2d_sbc.c @@ -0,0 +1,386 @@ +/***************************************************************************** +** +** Name: a2d_sbc.c +** +** Description:utility functions to help build and parse SBC +** Codec Information Element and Media Payload. +** Copyright (c) 2002-2004, WIDCOMM Inc., All Rights Reserved. +** WIDCOMM Bluetooth Core. Proprietary and confidential. +** +*****************************************************************************/ +#include "bt_target.h" + +#if (A2D_SBC_INCLUDED == TRUE) +#include <string.h> +#include "a2d_api.h" +#include "a2d_int.h" +#include "a2d_sbc.h" + +/************************************************************************************************* + * SBC descramble code + * Purpose: to tie the SBC code with BTE/mobile stack code, + * especially for the case when the SBC is ported into a third-party Multimedia chip + * + * Algorithm: + * init process: all counters reset to 0, + * calculate base_index: (6 + s16NumOfChannels*s16NumOfSubBands/2) + * scramble side: the init process happens every time SBC_Encoder_Init() is called. + * descramble side: it would be nice to know if he "init" process has happened. + * alter the SBC SYNC word 0x9C (1001 1100) to 0x8C (1000 1100). + * + * scramble process: + * The CRC byte: + * Every SBC frame has a frame header. + * The 1st byte is the sync word and the following 2 bytes are about the stream format. + * They are supposed to be "constant" within a "song" + * The 4th byte is the CRC byte. The CRC byte is bound to be random. + * Derive 2 items from the CRC byte; one is the "use" bit, the other is the "index". + * + * SBC keeps 2 sets of "use" & "index"; derived the current and the previous frame. + * + * The "use" bit is any bit in SBC_PRTC_USE_MASK is set. + * If set, SBC uses the "index" from the current frame. + * If not set, SBC uses the "index" from the previous frame or 0. + * + * index = (CRC & 0x3) + ((CRC & 0x30) >> 2) // 8 is the max index + * + * if(index > 0) + * { + * p = &u8frame[base_index]; + * if((index&1)&&(u16PacketLength > (base_index+index*2))) + * { + * // odd index: swap 2 bytes + * tmp = p[index]; + * p[index] = p[index*2]; + * p[index*2] = tmp; + * } + * else + * { + * // even index: shift by 3 + * tmp = (p[index] >> 3) + (p[index] << 5); + * p[index] = tmp; + * } + * } + * //else index is 0. The frame stays unaltered + * + */ +#define A2D_SBC_SYNC_WORD 0x9C +#define A2D_SBC_CRC_IDX 3 +#define A2D_SBC_USE_MASK 0x64 +#define A2D_SBC_SYNC_MASK 0x10 +#define A2D_SBC_CIDX 0 +#define A2D_SBC_LIDX 1 +#define A2D_SBC_CH_M_BITS 0xC /* channel mode bits: 0: mono; 1 ch */ +#define A2D_SBC_SUBBAND_BIT 0x1 /* num of subband bit: 0:4; 1: 8 */ + +#define A2D_SBC_GET_IDX(sc) (((sc) & 0x3) + (((sc) & 0x30) >> 2)) + +typedef struct +{ + UINT8 use; + UINT8 idx; +} tA2D_SBC_FR_CB; + +typedef struct +{ + tA2D_SBC_FR_CB fr[2]; + UINT8 index; + UINT8 base; +} tA2D_SBC_DS_CB; + +static tA2D_SBC_DS_CB a2d_sbc_ds_cb; +/*int a2d_count = 0;*/ +/****************************************************************************** +** +** Function A2D_SbcChkFrInit +** +** Description check if need to init the descramble control block. +** +** Returns nothing. +******************************************************************************/ +void A2D_SbcChkFrInit(UINT8 *p_pkt) +{ + UINT8 fmt; + UINT8 num_chnl = 1; + UINT8 num_subband = 4; + + if((p_pkt[0] & A2D_SBC_SYNC_MASK) == 0) + { + a2d_cb.use_desc = TRUE; + fmt = p_pkt[1]; + p_pkt[0] |= A2D_SBC_SYNC_MASK; + memset(&a2d_sbc_ds_cb, 0, sizeof(tA2D_SBC_DS_CB)); + if(fmt & A2D_SBC_CH_M_BITS) + num_chnl = 2; + if(fmt & A2D_SBC_SUBBAND_BIT) + num_subband = 8; + a2d_sbc_ds_cb.base = 6 + num_chnl*num_subband/2; + /*printf("base: %d\n", a2d_sbc_ds_cb.base); + a2d_count = 0;*/ + } +} + +/****************************************************************************** +** +** Function A2D_SbcDescramble +** +** Description descramble the packet. +** +** Returns nothing. +******************************************************************************/ +void A2D_SbcDescramble(UINT8 *p_pkt, UINT16 len) +{ + tA2D_SBC_FR_CB *p_cur, *p_last; + UINT32 idx, tmp, tmp2; + + if(a2d_cb.use_desc) + { + /* c2l */ + p_last = &a2d_sbc_ds_cb.fr[A2D_SBC_LIDX]; + p_cur = &a2d_sbc_ds_cb.fr[A2D_SBC_CIDX]; + p_last->idx = p_cur->idx; + p_last->use = p_cur->use; + /* getc */ + p_cur->use = p_pkt[A2D_SBC_CRC_IDX] & A2D_SBC_USE_MASK; + p_cur->idx = A2D_SBC_GET_IDX(p_pkt[A2D_SBC_CRC_IDX]); + a2d_sbc_ds_cb.index = (p_cur->use)?A2D_SBC_CIDX:A2D_SBC_LIDX; + /* + printf("%05d: ar[%02d]: x%02x, msk: x%02x, use: %s, idx: %02d, ", + a2d_count++, + A2D_SBC_CRC_IDX, p_pkt[A2D_SBC_CRC_IDX], A2D_SBC_USE_MASK, + (p_cur->use)?"cur":"lst", p_cur->idx); + */ + /* descramble */ + idx = a2d_sbc_ds_cb.fr[a2d_sbc_ds_cb.index].idx; + if(idx > 0) + { + p_pkt = &p_pkt[a2d_sbc_ds_cb.base]; + if((idx&1) && (len > (a2d_sbc_ds_cb.base+(idx<<1)))) + { + tmp2 = (idx<<1); + tmp = p_pkt[idx]; + p_pkt[idx] = p_pkt[tmp2]; + p_pkt[tmp2] = tmp; + /* + printf("tmp2: %02d, len: %d, idx: %d\n", + tmp2, len, a2d_sbc_ds_cb.fr[a2d_sbc_ds_cb.index].idx); + */ + } + else + { + tmp2 = p_pkt[idx]; + tmp = (tmp2>>3)+(tmp2<<5); + p_pkt[idx] = (UINT8)tmp; + /* + printf("tmp: x%02x, len: %d, idx: %d(cmp:%d)\n", + (UINT8)tmp2, len, a2d_sbc_ds_cb.fr[a2d_sbc_ds_cb.index].idx, + (a2d_sbc_ds_cb.base+(idx<<1))); + */ + } + } + /* + else + { + printf("!!!!\n"); + } + */ + } +} + +/****************************************************************************** +** +** Function A2D_BldSbcInfo +** +** Description This function is called by an application to build +** the SBC Media Codec Capabilities byte sequence +** beginning from the LOSC octet. +** Input Parameters: +** media_type: Indicates Audio, or Multimedia. +** +** p_ie: The SBC Codec Information Element information. +** +** Output Parameters: +** p_result: the resulting codec info byte sequence. +** +** Returns A2D_SUCCESS if function execution succeeded. +** Error status code, otherwise. +******************************************************************************/ +tA2D_STATUS A2D_BldSbcInfo(UINT8 media_type, tA2D_SBC_CIE *p_ie, UINT8 *p_result) +{ + tA2D_STATUS status; + + if( p_ie == NULL || p_result == NULL || + (p_ie->samp_freq & ~A2D_SBC_IE_SAMP_FREQ_MSK) || + (p_ie->ch_mode & ~A2D_SBC_IE_CH_MD_MSK) || + (p_ie->block_len & ~A2D_SBC_IE_BLOCKS_MSK) || + (p_ie->num_subbands & ~A2D_SBC_IE_SUBBAND_MSK) || + (p_ie->alloc_mthd & ~A2D_SBC_IE_ALLOC_MD_MSK) || + (p_ie->max_bitpool < p_ie->min_bitpool) || + (p_ie->max_bitpool < A2D_SBC_IE_MIN_BITPOOL) || + (p_ie->max_bitpool > A2D_SBC_IE_MAX_BITPOOL) || + (p_ie->min_bitpool < A2D_SBC_IE_MIN_BITPOOL) || + (p_ie->min_bitpool > A2D_SBC_IE_MAX_BITPOOL) ) + { + /* if any unused bit is set */ + status = A2D_INVALID_PARAMS; + } + else + { + status = A2D_SUCCESS; + *p_result++ = A2D_SBC_INFO_LEN; + *p_result++ = media_type; + *p_result++ = A2D_MEDIA_CT_SBC; + + /* Media Codec Specific Information Element */ + *p_result++ = p_ie->samp_freq | p_ie->ch_mode; + + *p_result++ = p_ie->block_len | p_ie->num_subbands | p_ie->alloc_mthd; + + *p_result++ = p_ie->min_bitpool; + *p_result = p_ie->max_bitpool; + } + return status; +} + +/****************************************************************************** +** +** Function A2D_ParsSbcInfo +** +** Description This function is called by an application to parse +** the SBC Media Codec Capabilities byte sequence +** beginning from the LOSC octet. +** Input Parameters: +** p_info: the byte sequence to parse. +** +** for_caps: TRUE, if the byte sequence is for get capabilities response. +** +** Output Parameters: +** p_ie: The SBC Codec Information Element information. +** +** Returns A2D_SUCCESS if function execution succeeded. +** Error status code, otherwise. +******************************************************************************/ +tA2D_STATUS A2D_ParsSbcInfo(tA2D_SBC_CIE *p_ie, UINT8 *p_info, BOOLEAN for_caps) +{ + tA2D_STATUS status; + UINT8 losc; + UINT8 mt; + + if( p_ie == NULL || p_info == NULL) + status = A2D_INVALID_PARAMS; + else + { + losc = *p_info++; + mt = *p_info++; + /* If the function is called for the wrong Media Type or Media Codec Type */ + if(losc != A2D_SBC_INFO_LEN || *p_info != A2D_MEDIA_CT_SBC) + status = A2D_WRONG_CODEC; + else + { + p_info++; + p_ie->samp_freq = *p_info & A2D_SBC_IE_SAMP_FREQ_MSK; + p_ie->ch_mode = *p_info & A2D_SBC_IE_CH_MD_MSK; + p_info++; + p_ie->block_len = *p_info & A2D_SBC_IE_BLOCKS_MSK; + p_ie->num_subbands = *p_info & A2D_SBC_IE_SUBBAND_MSK; + p_ie->alloc_mthd = *p_info & A2D_SBC_IE_ALLOC_MD_MSK; + p_info++; + p_ie->min_bitpool = *p_info++; + p_ie->max_bitpool = *p_info; + status = A2D_SUCCESS; + if(p_ie->min_bitpool < A2D_SBC_IE_MIN_BITPOOL || p_ie->min_bitpool > A2D_SBC_IE_MAX_BITPOOL ) + status = A2D_BAD_MIN_BITPOOL; + + if(p_ie->max_bitpool < A2D_SBC_IE_MIN_BITPOOL || p_ie->max_bitpool > A2D_SBC_IE_MAX_BITPOOL || + p_ie->max_bitpool < p_ie->min_bitpool) + status = A2D_BAD_MAX_BITPOOL; + + if(for_caps == FALSE) + { + if(A2D_BitsSet(p_ie->samp_freq) != A2D_SET_ONE_BIT) + status = A2D_BAD_SAMP_FREQ; + if(A2D_BitsSet(p_ie->ch_mode) != A2D_SET_ONE_BIT) + status = A2D_BAD_CH_MODE; + if(A2D_BitsSet(p_ie->block_len) != A2D_SET_ONE_BIT) + status = A2D_BAD_BLOCK_LEN; + if(A2D_BitsSet(p_ie->num_subbands) != A2D_SET_ONE_BIT) + status = A2D_BAD_SUBBANDS; + if(A2D_BitsSet(p_ie->alloc_mthd) != A2D_SET_ONE_BIT) + status = A2D_BAD_ALLOC_MTHD; + } + } + } + return status; +} + +/****************************************************************************** +** +** Function A2D_BldSbcMplHdr +** +** Description This function is called by an application to parse +** the SBC Media Payload header. +** Input Parameters: +** frag: 1, if fragmented. 0, otherwise. +** +** start: 1, if the starting packet of a fragmented frame. +** +** last: 1, if the last packet of a fragmented frame. +** +** num: If frag is 1, this is the number of remaining fragments +** (including this fragment) of this frame. +** If frag is 0, this is the number of frames in this packet. +** +** Output Parameters: +** p_dst: the resulting media payload header byte sequence. +** +** Returns void. +******************************************************************************/ +void A2D_BldSbcMplHdr(UINT8 *p_dst, BOOLEAN frag, BOOLEAN start, BOOLEAN last, UINT8 num) +{ + if(p_dst) + { + *p_dst = 0; + if(frag) + *p_dst |= A2D_SBC_HDR_F_MSK; + if(start) + *p_dst |= A2D_SBC_HDR_S_MSK; + if(last) + *p_dst |= A2D_SBC_HDR_L_MSK; + *p_dst |= (A2D_SBC_HDR_NUM_MSK & num); + } +} + +/****************************************************************************** +** +** Function A2D_ParsSbcMplHdr +** +** Description This function is called by an application to parse +** the SBC Media Payload header. +** Input Parameters: +** p_src: the byte sequence to parse.. +** +** Output Parameters: +** frag: 1, if fragmented. 0, otherwise. +** +** start: 1, if the starting packet of a fragmented frame. +** +** last: 1, if the last packet of a fragmented frame. +** +** num: If frag is 1, this is the number of remaining fragments +** (including this fragment) of this frame. +** If frag is 0, this is the number of frames in this packet. +** +** Returns void. +******************************************************************************/ +void A2D_ParsSbcMplHdr(UINT8 *p_src, BOOLEAN *p_frag, BOOLEAN *p_start, BOOLEAN *p_last, UINT8 *p_num) +{ + if(p_src && p_frag && p_start && p_last && p_num) + { + *p_frag = (*p_src & A2D_SBC_HDR_F_MSK) ? TRUE: FALSE; + *p_start= (*p_src & A2D_SBC_HDR_S_MSK) ? TRUE: FALSE; + *p_last = (*p_src & A2D_SBC_HDR_L_MSK) ? TRUE: FALSE; + *p_num = (*p_src & A2D_SBC_HDR_NUM_MSK); + } +} + +#endif /* A2D_SBC_INCLUDED == TRUE */ |