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Diffstat (limited to 'ext/ogg/vorbis_parse.c')
| -rw-r--r-- | ext/ogg/vorbis_parse.c | 239 |
1 files changed, 0 insertions, 239 deletions
diff --git a/ext/ogg/vorbis_parse.c b/ext/ogg/vorbis_parse.c deleted file mode 100644 index f9ba746d..00000000 --- a/ext/ogg/vorbis_parse.c +++ /dev/null @@ -1,239 +0,0 @@ -/* - This file borrowed from liboggz - */ -/* - Copyright (C) 2003 Commonwealth Scientific and Industrial Research - Organisation (CSIRO) Australia - - Redistribution and use in source and binary forms, with or without - modification, are permitted provided that the following conditions - are met: - - - Redistributions of source code must retain the above copyright - notice, this list of conditions and the following disclaimer. - - - Redistributions in binary form must reproduce the above copyright - notice, this list of conditions and the following disclaimer in the - documentation and/or other materials provided with the distribution. - - - Neither the name of CSIRO Australia nor the names of its - contributors may be used to endorse or promote products derived from - this software without specific prior written permission. - - THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS - ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT - LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A - PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE ORGANISATION OR - CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, - EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, - PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR - PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF - LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING - NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS - SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. -*/ - -/* - * oggz_auto.c - * - * Conrad Parker <conrad@annodex.net> - */ - -#include "config.h" - -#include <stdlib.h> -#include <string.h> - -#include "gstoggstream.h" - -/* - * Vorbis packets can be short or long, and each packet overlaps the previous - * and next packets. The granulepos of a packet is always the last sample - * that is completely decoded at the end of decoding that packet - i.e. the - * last packet before the first overlapping packet. If the sizes of packets - * are 's' and 'l', then the increment will depend on the previous and next - * packet types: - * v prev<<1 | next - * lll: l/2 3 - * lls: 3l/4 - s/4 2 - * lsl: s/2 - * lss: s/2 - * sll: l/4 + s/4 1 - * sls: l/2 0 - * ssl: s/2 - * sss: s/2 - * - * The previous and next packet types can be inferred from the current packet - * (additional information is not required) - * - * The two blocksizes can be determined from the first header packet, by reading - * byte 28. 1 << (packet[28] >> 4) == long_size. - * 1 << (packet[28] & 0xF) == short_size. - * - * (see http://xiph.org/vorbis/doc/Vorbis_I_spec.html for specification) - */ - - -void -parse_vorbis_header_packet (GstOggStream * pad, ogg_packet * packet) -{ - /* - * on the first (b_o_s) packet, determine the long and short sizes, - * and then calculate l/2, l/4 - s/4, 3 * l/4 - s/4, l/2 - s/2 and s/2 - */ - int short_size; - int long_size; - - long_size = 1 << (packet->packet[28] >> 4); - short_size = 1 << (packet->packet[28] & 0xF); - - pad->nln_increments[3] = long_size >> 1; - pad->nln_increments[2] = 3 * (long_size >> 2) - (short_size >> 2); - pad->nln_increments[1] = (long_size >> 2) + (short_size >> 2); - pad->nln_increments[0] = pad->nln_increments[3]; - pad->short_size = short_size; - pad->long_size = long_size; - pad->nsn_increment = short_size >> 1; -} - -void -parse_vorbis_setup_packet (GstOggStream * pad, ogg_packet * op) -{ - /* - * the code pages, a whole bunch of other fairly useless stuff, AND, - * RIGHT AT THE END (of a bunch of variable-length compressed rubbish that - * basically has only one actual set of values that everyone uses BUT YOU - * CAN'T BE SURE OF THAT, OH NO YOU CAN'T) is the only piece of data that's - * actually useful to us - the packet modes (because it's inconceivable to - * think people might want _just that_ and nothing else, you know, for - * seeking and stuff). - * - * Fortunately, because of the mandate that non-used bits must be zero - * at the end of the packet, we might be able to sneakily work backwards - * and find out the information we need (namely a mapping of modes to - * packet sizes) - */ - unsigned char *current_pos = &op->packet[op->bytes - 1]; - int offset; - int size; - int size_check; - int *mode_size_ptr; - int i; - int ii; - - /* - * This is the format of the mode data at the end of the packet for all - * Vorbis Version 1 : - * - * [ 6:number_of_modes ] - * [ 1:size | 16:window_type(0) | 16:transform_type(0) | 8:mapping ] - * [ 1:size | 16:window_type(0) | 16:transform_type(0) | 8:mapping ] - * [ 1:size | 16:window_type(0) | 16:transform_type(0) | 8:mapping ] - * [ 1:framing(1) ] - * - * e.g.: - * - * <- - * 0 0 0 0 0 1 0 0 - * 0 0 1 0 0 0 0 0 - * 0 0 1 0 0 0 0 0 - * 0 0 1|0 0 0 0 0 - * 0 0 0 0|0|0 0 0 - * 0 0 0 0 0 0 0 0 - * 0 0 0 0|0 0 0 0 - * 0 0 0 0 0 0 0 0 - * 0 0 0 0|0 0 0 0 - * 0 0 0|1|0 0 0 0 | - * 0 0 0 0 0 0 0 0 V - * 0 0 0|0 0 0 0 0 - * 0 0 0 0 0 0 0 0 - * 0 0 1|0 0 0 0 0 - * 0 0|1|0 0 0 0 0 - * - * - * i.e. each entry is an important bit, 32 bits of 0, 8 bits of blah, a - * bit of 1. - * Let's find our last 1 bit first. - * - */ - - size = 0; - - offset = 8; - while (!((1 << --offset) & *current_pos)) { - if (offset == 0) { - offset = 8; - current_pos -= 1; - } - } - - while (1) { - - /* - * from current_pos-5:(offset+1) to current_pos-1:(offset+1) should - * be zero - */ - offset = (offset + 7) % 8; - if (offset == 7) - current_pos -= 1; - - if (((current_pos[-5] & ~((1 << (offset + 1)) - 1)) != 0) - || - current_pos[-4] != 0 - || - current_pos[-3] != 0 - || - current_pos[-2] != 0 - || ((current_pos[-1] & ((1 << (offset + 1)) - 1)) != 0) - ) { - break; - } - - size += 1; - - current_pos -= 5; - - } - - /* Give ourselves a chance to recover if we went back too far by using - * the size check. */ - for (ii = 0; ii < 2; ii++) { - if (offset > 4) { - size_check = (current_pos[0] >> (offset - 5)) & 0x3F; - } else { - /* mask part of byte from current_pos */ - size_check = (current_pos[0] & ((1 << (offset + 1)) - 1)); - /* shift to appropriate position */ - size_check <<= (5 - offset); - /* or in part of byte from current_pos - 1 */ - size_check |= (current_pos[-1] & ~((1 << (offset + 3)) - 1)) >> - (offset + 3); - } - - size_check += 1; - if (size_check == size) { - break; - } - offset = (offset + 1) % 8; - if (offset == 0) - current_pos += 1; - current_pos += 5; - size -= 1; - } - - /* Store mode size information in our info struct */ - i = -1; - while ((1 << (++i)) < size); - pad->vorbis_log2_num_modes = i; - - mode_size_ptr = pad->vorbis_mode_sizes; - - for (i = 0; i < size; i++) { - offset = (offset + 1) % 8; - if (offset == 0) - current_pos += 1; - *mode_size_ptr++ = (current_pos[0] >> offset) & 0x1; - current_pos += 5; - } - -} |