hcr.c

这是著名的TCPMP播放器在WINDWOWS,和WINCE下编译通过的源程序.笔者对其中的LIBMAD库做了针对ARM MPU的优化. 并增加了词幕功能.

{
    codeword[index].sp_offset = sp;
    codeword[index].cb = cb;
    codeword[index].decoded = 0;
    codeword[index].bits.len = 0;
}

uint8_t reordered_spectral_data(NeAACDecHandle hDecoder, ic_stream *ics, 
                                bitfile *ld, int16_t *spectral_data)
{   
    uint16_t PCWs_done;
    uint16_t numberOfSegments, numberOfSets, numberOfCodewords;  

    codeword_t codeword[512];
    bits_t segment[512];

    uint16_t sp_offset[8];
    uint16_t g, i, sortloop, set, bitsread;
    uint8_t w_idx, sfb, this_CB, last_CB, this_sec_CB; 
    
    const uint16_t nshort = hDecoder->frameLength/8;
    const uint16_t sp_data_len = ics->length_of_reordered_spectral_data;
    
    const uint8_t *PreSortCb;

	memset(spectral_data,0,sizeof(int16_t)*1024);

    /* no data (e.g. silence) */
    if (sp_data_len == 0)
        return 0;

    /* since there is spectral data, at least one codeword has nonzero length */
    if (ics->length_of_longest_codeword == 0)
        return 10;
    
    if (sp_data_len < ics->length_of_longest_codeword)
        return 10; 

    sp_offset[0] = 0;
    for (g = 1; g < ics->num_window_groups; g++)
    {
        sp_offset[g] = sp_offset[g-1] + nshort*ics->window_group_length[g-1];
    }

    PCWs_done = 0;
    numberOfSegments = 0;
    numberOfCodewords = 0;
    bitsread = 0;

    /* VCB11 code books in use */
    if (hDecoder->aacSectionDataResilienceFlag)
    {
        PreSortCb = PreSortCB_ER;
        last_CB = NUM_CB_ER;
    } else
    {
        PreSortCb = PreSortCB_STD;
        last_CB = NUM_CB;
    }
 
    /* step 1: decode PCW's (set 0), and stuff data in easier-to-use format */
    for (sortloop = 0; sortloop < last_CB; sortloop++)
    {
        /* select codebook to process this pass */
        this_CB = PreSortCb[sortloop];
        
        /* loop over sfbs */
        for (sfb = 0; sfb < ics->max_sfb; sfb++)
        {
            /* loop over all in this sfb, 4 lines per loop */
            for (w_idx = 0; 4*w_idx < (ics->swb_offset[sfb+1] - ics->swb_offset[sfb]); w_idx++)
            {
                for(g = 0; g < ics->num_window_groups; g++)
                {
                    for (i = 0; i < ics->num_sec[g]; i++)
                    {
                        /* check whether sfb used here is the one we want to process */
                        if ((ics->sect_start[g][i] <= sfb) && (ics->sect_end[g][i] > sfb))
                        {                            
                            /* check whether codebook used here is the one we want to process */
                            this_sec_CB = ics->sect_cb[g][i];
                 
                            if (is_good_cb(this_CB, this_sec_CB))                              
                            {
                                /* precalculate some stuff */
                                uint16_t sect_sfb_size = ics->sect_sfb_offset[g][sfb+1] - ics->sect_sfb_offset[g][sfb];
                                uint8_t inc = (this_sec_CB < FIRST_PAIR_HCB) ? QUAD_LEN : PAIR_LEN;
                                uint16_t group_cws_count = (4*ics->window_group_length[g])/inc;
                                uint8_t segwidth = segmentWidth(this_sec_CB);
                                uint16_t cws;                                

                                /* read codewords until end of sfb or end of window group (shouldn't only 1 trigger?) */                                 
                                for (cws = 0; (cws < group_cws_count) && ((cws + w_idx*group_cws_count) < sect_sfb_size); cws++)
                                {
                                    uint16_t sp = sp_offset[g] + ics->sect_sfb_offset[g][sfb] + inc * (cws + w_idx*group_cws_count);                                   

                                    /* read and decode PCW */
                                    if (!PCWs_done)
                                    {         
                                        /* read in normal segments */
                                        if (bitsread + segwidth <= sp_data_len)
                                        {                                            
                                            read_segment(&segment[numberOfSegments], segwidth, ld);                          
                                            bitsread += segwidth;
                                            
                                            huffman_spectral_data_2(this_sec_CB, &segment[numberOfSegments], &spectral_data[sp]);                                            

                                            /* keep leftover bits */
                                            rewrev_bits(&segment[numberOfSegments]);

                                            numberOfSegments++;
                                        } else {
                                            /* remaining stuff after last segment, we unfortunately couldn't read
                                               this in earlier because it might not fit in 64 bits. since we already
                                               decoded (and removed) the PCW it is now guaranteed to fit */
                                            if (bitsread < sp_data_len)
                                            {                                                
                                                const uint8_t additional_bits = sp_data_len - bitsread;                                               

                                                read_segment(&segment[numberOfSegments], additional_bits, ld);                                                
                                                segment[numberOfSegments].len += segment[numberOfSegments-1].len;
                                                rewrev_bits(&segment[numberOfSegments]);                                               

                                                if (segment[numberOfSegments-1].len > 32)
                                                {
                                                    segment[numberOfSegments-1].bufb = segment[numberOfSegments].bufb + 
                                                        showbits_hcr(&segment[numberOfSegments-1], segment[numberOfSegments-1].len - 32);
                                                    segment[numberOfSegments-1].bufa = segment[numberOfSegments].bufa + 
                                                        showbits_hcr(&segment[numberOfSegments-1], 32);
                                                } else {
                                                    segment[numberOfSegments-1].bufa = segment[numberOfSegments].bufa + 
                                                        showbits_hcr(&segment[numberOfSegments-1], segment[numberOfSegments-1].len);
                                                    segment[numberOfSegments-1].bufb = segment[numberOfSegments].bufb;
                                                }                                                
                                                segment[numberOfSegments-1].len += additional_bits;
                                            }
                                            bitsread = sp_data_len;
                                            PCWs_done = 1;

                                            fill_in_codeword(codeword, 0, sp, this_sec_CB);                                            
                                        }
                                    } else {    
                                        fill_in_codeword(codeword, numberOfCodewords - numberOfSegments, sp, this_sec_CB);                                         
                                    }
                                    numberOfCodewords++;
                                }                             
                            }
                        }
                    } 
                 } 
             }
         }
    }

    if (numberOfSegments == 0)
        return 10; 

    numberOfSets = numberOfCodewords / numberOfSegments;     

    /* step 2: decode nonPCWs */
    for (set = 1; set <= numberOfSets; set++)
    {
        uint16_t trial;

        for (trial = 0; trial < numberOfSegments; trial++)
        {
            uint16_t codewordBase;

            for (codewordBase = 0; codewordBase < numberOfSegments; codewordBase++)
            {
                const uint16_t segment_idx = (trial + codewordBase) % numberOfSegments;
                const uint16_t codeword_idx = codewordBase + set*numberOfSegments - numberOfSegments;

                /* data up */
                if (codeword_idx >= numberOfCodewords - numberOfSegments) break;

                if (!codeword[codeword_idx].decoded && segment[segment_idx].len > 0)
                {
                    uint8_t tmplen;

                    if (codeword[codeword_idx].bits.len != 0)                   
                        concat_bits(&segment[segment_idx], &codeword[codeword_idx].bits);                            
                    
                    tmplen = segment[segment_idx].len;

                    if (huffman_spectral_data_2(codeword[codeword_idx].cb, &segment[segment_idx],
                                               &spectral_data[codeword[codeword_idx].sp_offset]) >= 0)
                    {
                        codeword[codeword_idx].decoded = 1;
                    } else 
                    {   
                        codeword[codeword_idx].bits = segment[segment_idx];
                        codeword[codeword_idx].bits.len = tmplen;                        
                    }
                                            
                }
            }
        }
        for (i = 0; i < numberOfSegments; i++)
            rewrev_bits(&segment[i]);
    }

    return 0;
}
#endif