diff options
| -rw-r--r-- | src/libxineadec/adpcm.c | 146 |
1 files changed, 129 insertions, 17 deletions
diff --git a/src/libxineadec/adpcm.c b/src/libxineadec/adpcm.c index dd7e41c84..46ac42162 100644 --- a/src/libxineadec/adpcm.c +++ b/src/libxineadec/adpcm.c @@ -24,7 +24,7 @@ * formats can be found here: * http://www.pcisys.net/~melanson/codecs/ * - * $Id: adpcm.c,v 1.10 2002/08/05 00:20:35 tmmm Exp $ + * $Id: adpcm.c,v 1.11 2002/09/02 17:25:45 tmmm Exp $ */ #include <stdio.h> @@ -123,10 +123,30 @@ typedef struct adpcm_decoder_s { } adpcm_decoder_t; +/* + * decode_ima_nibbles + * + * So many different audio encoding formats leverage off of the IMA + * ADPCM algorithm that it makes sense to create a function that takes + * care of handling the common decoding portion. + * + * This function takes a buffer of ADPCM nibbles that are stored in an + * array of signed 16-bit numbers. The function then decodes the nibbles + * in place so that the buffer contains the decoded audio when the function + * is finished. + * + * The addresses of the initial predictor and index values are passed, + * rather than their values, so that the function can return the final + * predictor and index values after decoding. This is done in case the + * calling function cares (in the case of IMA ADPCM from Westwood Studios' + * VQA files, the values are initialized to 0 at the beginning of the file + * and maintained throughout all of the IMA blocks). + */ static void decode_ima_nibbles(unsigned short *output, int output_size, int channels, - int predictor_l, int index_l, - int predictor_r, int index_r) { + int *predictor_l, int *index_l, + int *predictor_r, int *index_r) { + int step[2]; int predictor[2]; int index[2]; @@ -136,12 +156,12 @@ static void decode_ima_nibbles(unsigned short *output, int delta; int channel_number = 0; - step[0] = ima_adpcm_step[index_l]; - step[1] = ima_adpcm_step[index_r]; - predictor[0] = predictor_l; - predictor[1] = predictor_r; - index[0] = index_l; - index[1] = index_r; + step[0] = ima_adpcm_step[*index_l]; + step[1] = ima_adpcm_step[*index_r]; + predictor[0] = *predictor_l; + predictor[1] = *predictor_r; + index[0] = *index_l; + index[1] = *index_r; for (i = 0; i < output_size; i++) { delta = output[i]; @@ -169,6 +189,12 @@ static void decode_ima_nibbles(unsigned short *output, /* toggle channel */ channel_number ^= channels - 1; } + + /* save the index and predictor values in case the calling function cares */ + *predictor_l = predictor[0]; + *predictor_r = predictor[1]; + *index_l = index[0]; + *index_r = index[1]; } #define DK3_GET_NEXT_NIBBLE() \ @@ -389,8 +415,8 @@ static void dk4_adpcm_decode_block(adpcm_decoder_t *this, buf_element_t *buf) { decode_ima_nibbles(&this->decode_buffer[this->channels], out_ptr - this->channels, this->channels, - predictor_l, index_l, - predictor_r, index_r); + &predictor_l, &index_l, + &predictor_r, &index_r); /* dispatch the decoded audio */ j = 0; @@ -499,8 +525,8 @@ static void ms_ima_adpcm_decode_block(adpcm_decoder_t *this, decode_ima_nibbles(this->decode_buffer, this->out_block_size, this->channels, - predictor_l, index_l, - predictor_r, index_r); + &predictor_l, &index_l, + &predictor_r, &index_r); /* dispatch the decoded audio */ j = 0; @@ -626,8 +652,8 @@ static void qt_ima_adpcm_decode_block(adpcm_decoder_t *this, decode_ima_nibbles(&output[out_ptr], QT_IMA_ADPCM_SAMPLES_PER_BLOCK * this->channels, this->channels, - initial_predictor_l, initial_index_l, - initial_predictor_r, initial_index_r); + &initial_predictor_l, &initial_index_l, + &initial_predictor_r, &initial_index_r); out_ptr += QT_IMA_ADPCM_SAMPLES_PER_BLOCK * this->channels; } @@ -821,7 +847,7 @@ static void smjpeg_adpcm_decode_block(adpcm_decoder_t *this, buf_element_t *buf) decode_ima_nibbles(this->decode_buffer, out_ptr, 1, - predictor, index, + &predictor, &index, 0, 0); /* dispatch the decoded audio */ @@ -855,6 +881,79 @@ static void smjpeg_adpcm_decode_block(adpcm_decoder_t *this, buf_element_t *buf) this->size = 0; } +static void vqa_adpcm_decode_block(adpcm_decoder_t *this, buf_element_t *buf) { + + /* VQA IMA blocks do not have a preamble with an initial index and + * predictor; there is one master index and predictor pair per channel that + * is initialized to 0 and maintained throughout all of the VQA IMA + * blocks. (That is why the following variables are static.) */ + static int index_l = 0; + static int index_r = 0; + static int predictor_l = 0; + static int predictor_r = 0; + + int out_ptr = 0; + int i; + audio_buffer_t *audio_buffer; + int bytes_to_send; + + /* break apart the ADPCM nibbles */ + for (i = 0; i < this->size; i++) { + if (this->channels == 1) { + this->decode_buffer[out_ptr++] = this->buf[i] & 0x0F; + this->decode_buffer[out_ptr++] = (this->buf[i] >> 4) & 0x0F; + } else { + if ((i & 0x1) == 0) { + /* left channel */ + this->decode_buffer[out_ptr + 0] = this->buf[i] & 0x0F; + this->decode_buffer[out_ptr + 2] = (this->buf[i] >> 4) & 0x0F; + } else { + /* right channel */ + this->decode_buffer[out_ptr + 1] = this->buf[i] & 0x0F; + this->decode_buffer[out_ptr + 3] = (this->buf[i] >> 4) & 0x0F; + out_ptr += 4; + } + } + } + + /* process the nibbles */ + decode_ima_nibbles(this->decode_buffer, + out_ptr, + this->channels, + &predictor_l, &index_l, + &predictor_r, &index_r); + + /* dispatch the decoded audio */ + i = 0; + while (i < out_ptr) { + audio_buffer = this->audio_out->get_buffer (this->audio_out); + if (audio_buffer->mem_size == 0) { + printf ("adpcm: Help! Allocated audio buffer with nothing in it!\n"); + return; + } + + /* out_ptr and i are sample counts, mem_size is a byte count */ + if (((out_ptr - i) * 2) > audio_buffer->mem_size) + bytes_to_send = audio_buffer->mem_size; + else + bytes_to_send = (out_ptr - i) * 2; + + xine_fast_memcpy(audio_buffer->mem, &this->decode_buffer[i], + bytes_to_send); + /* byte count / 2 (bytes / sample) / channels */ + audio_buffer->num_frames = bytes_to_send / 2 / this->channels; + + audio_buffer->vpts = buf->pts; + buf->pts = 0; /* only first buffer gets the real pts */ + this->audio_out->put_buffer (this->audio_out, audio_buffer); + + i += bytes_to_send / 2; /* 2 bytes per sample */ + } + + /* reset buffer */ + this->size = 0; +} + static int adpcm_can_handle (audio_decoder_t *this_gen, int buf_type) { buf_type &= 0xFFFF0000; @@ -863,7 +962,8 @@ static int adpcm_can_handle (audio_decoder_t *this_gen, int buf_type) { buf_type == BUF_AUDIO_QTIMAADPCM || buf_type == BUF_AUDIO_DK3ADPCM || buf_type == BUF_AUDIO_DK4ADPCM || - buf_type == BUF_AUDIO_SMJPEG_IMA ); + buf_type == BUF_AUDIO_SMJPEG_IMA || + buf_type == BUF_AUDIO_VQA_IMA ); } static void adpcm_reset (audio_decoder_t *this_gen) { @@ -948,6 +1048,14 @@ static void adpcm_decode_data (audio_decoder_t *this_gen, buf_element_t *buf) { this->decode_buffer = NULL; } + /* make this decode buffer large enough to hold a second of decoded + * audio */ + if (buf->type == BUF_AUDIO_VQA_IMA) { + this->out_block_size = this->rate * this->channels; + /* allocate 2 bytes per sample */ + this->decode_buffer = xine_xmalloc(this->out_block_size * 2); + } + return; } @@ -1001,6 +1109,10 @@ static void adpcm_decode_data (audio_decoder_t *this_gen, buf_element_t *buf) { case BUF_AUDIO_SMJPEG_IMA: smjpeg_adpcm_decode_block(this, buf); break; + + case BUF_AUDIO_VQA_IMA: + vqa_adpcm_decode_block(this, buf); + break; } } } |