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2c98438c99
Original commit message from CVS: New dxr3 plugins from Martin Soto <soto@informatik.uni-kl.de>
255 lines
7.5 KiB
C
255 lines
7.5 KiB
C
/* GStreamer
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* Copyright (C) 2003 Martin Soto <martinsoto@users.sourceforge.net>
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*
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* ac3_padder.c: Pad AC3 frames for use with an SPDIF interface.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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#include <stdio.h>
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#include <string.h>
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#include "ac3_padder.h"
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#define IEC61937_DATA_TYPE_AC3 1
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struct frmsize_s
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{
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unsigned short bit_rate;
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unsigned short frm_size[3];
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};
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static const struct frmsize_s frmsizecod_tbl[64] =
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{
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{ 32 ,{64 ,69 ,96 } },
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{ 32 ,{64 ,70 ,96 } },
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{ 40 ,{80 ,87 ,120 } },
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{ 40 ,{80 ,88 ,120 } },
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{ 48 ,{96 ,104 ,144 } },
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{ 48 ,{96 ,105 ,144 } },
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{ 56 ,{112 ,121 ,168 } },
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{ 56 ,{112 ,122 ,168 } },
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{ 64 ,{128 ,139 ,192 } },
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{ 64 ,{128 ,140 ,192 } },
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{ 80 ,{160 ,174 ,240 } },
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{ 80 ,{160 ,175 ,240 } },
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{ 96 ,{192 ,208 ,288 } },
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{ 96 ,{192 ,209 ,288 } },
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{ 112 ,{224 ,243 ,336 } },
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{ 112 ,{224 ,244 ,336 } },
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{ 128 ,{256 ,278 ,384 } },
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{ 128 ,{256 ,279 ,384 } },
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{ 160 ,{320 ,348 ,480 } },
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{ 160 ,{320 ,349 ,480 } },
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{ 192 ,{384 ,417 ,576 } },
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{ 192 ,{384 ,418 ,576 } },
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{ 224 ,{448 ,487 ,672 } },
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{ 224 ,{448 ,488 ,672 } },
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{ 256 ,{512 ,557 ,768 } },
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{ 256 ,{512 ,558 ,768 } },
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{ 320 ,{640 ,696 ,960 } },
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{ 320 ,{640 ,697 ,960 } },
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{ 384 ,{768 ,835 ,1152 } },
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{ 384 ,{768 ,836 ,1152 } },
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{ 448 ,{896 ,975 ,1344 } },
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{ 448 ,{896 ,976 ,1344 } },
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{ 512 ,{1024 ,1114 ,1536 } },
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{ 512 ,{1024 ,1115 ,1536 } },
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{ 576 ,{1152 ,1253 ,1728 } },
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{ 576 ,{1152 ,1254 ,1728 } },
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{ 640 ,{1280 ,1393 ,1920 } },
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{ 640 ,{1280 ,1394 ,1920 } }
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};
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/* Go one byte forward in the input buffer. */
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#define ac3p_in_fw(padder) ((padder)->in_ptr++, (padder)->remaining--)
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/* Go one byte forward in the output buffer. */
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#define ac3p_out_fw(padder) ((padder)->out_ptr++, (padder)->bytes_to_copy--)
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/**
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* ac3p_init
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* @padder: The padder structure to initialize.
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*
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* Initializes an AC3 stream padder. This structure can be
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* subsequently used to parse an AC3 stream and convert it to IEC958
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* (S/PDIF) padded packets.
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*/
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extern void
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ac3p_init(ac3_padder *padder)
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{
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const char sync[4] = { 0x72, 0xF8, 0x1F, 0x4E };
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padder->state = AC3P_STATE_SYNC1;
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/* No material to read yet. */
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padder->remaining = 0;
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/* Initialize the sync bytes in the frame. */
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memcpy(padder->frame.header, sync, 4);
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}
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/**
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* ac3_push_data
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* @padder The padder structure.
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* @data A pointer to a buffer with new data to parse. This should
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* correspond to a new piece of a stream containing raw AC3 data.
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* @size The number of available bytes in the buffer.
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*
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* Pushes a new buffer of data to be parsed by the ac3 padder. The
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* ac3_parse() function will actually parse the data and report when
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* new frames are found. This funcion should only be called once at
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* the beginning of the parsing process, or when the ac3_parse()
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* function returns the %AC3P_EVENT_PUSH event.
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*/
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extern void
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ac3p_push_data(ac3_padder *padder, guchar *data, guint size)
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{
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padder->in_ptr = data;
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padder->remaining = size;
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}
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/**
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* ac3p_parse
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* @padder The padder structure.
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*
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* Parses the bytes already pushed into the padder structure (see
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* ac3p_push_data()) and returns an event value depending on the
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* results of the parsing.
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*
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* Returns: %AC3P_EVENT_FRAME to indicate that a new AC3 was found and
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* padded for IEC958 transmission. This frame can be read inmediatly
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* with ac3p_frame(). %AC3P_EVENT_PUSH to indicate that new data from
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* the input stream must be pushed into the padder using
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* ac3p_push_data(). This function should be called again after
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* pushing the data.
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*/
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extern int
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ac3p_parse(ac3_padder *padder)
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{
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while (padder->remaining > 0) {
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switch (padder->state) {
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case AC3P_STATE_SYNC1:
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if (*(padder->in_ptr) == 0x0b) {
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/* The first sync byte was found. Go to the next state. */
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padder->frame.sync_byte1 = 0x0b;
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padder->state = AC3P_STATE_SYNC2;
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}
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ac3p_in_fw(padder);
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break;
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case AC3P_STATE_SYNC2:
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if (*(padder->in_ptr) == 0x77) {
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/* The second sync byte was seen right after the first. Go to
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the next state. */
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padder->frame.sync_byte2 = 0x77;
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padder->state = AC3P_STATE_HEADER;
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/* Skip one byte. */
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ac3p_in_fw(padder);
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/* Prepare for reading the header. */
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padder->out_ptr = (guchar *) &(padder->frame.crc1);
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/* Discount the 2 sync bytes from the header size. */
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padder->bytes_to_copy = AC3P_AC3_HEADER_SIZE - 2;
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}
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else {
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/* The second sync byte was not seen. Go back to the
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first state. */
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padder->state = AC3P_STATE_SYNC1;
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}
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break;
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case AC3P_STATE_HEADER:
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if (padder->bytes_to_copy > 0) {
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/* Copy one byte. */
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*(padder->out_ptr) = *(padder->in_ptr);
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ac3p_in_fw(padder);
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ac3p_out_fw(padder);
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}
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else {
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int fscod;
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/* The header is ready: */
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fscod = (padder->frame.code >> 6) & 0x03;
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/* Calculate the frame size. */
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padder->ac3_frame_size =
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2 * frmsizecod_tbl[padder->frame.code & 0x3f].frm_size[fscod];
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/* Set up the IEC header. */
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if (padder->ac3_frame_size > 0) {
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padder->frame.header[4] = IEC61937_DATA_TYPE_AC3;
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}
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else {
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/* Don't know what it is, better be careful. */
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padder->state = AC3P_STATE_SYNC1;
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break;
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}
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padder->frame.header[5] = 0x00;
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padder->frame.header[6] = (padder->ac3_frame_size*8) & 0xFF;
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padder->frame.header[7] = ((padder->ac3_frame_size*8) >> 8) & 0xFF;
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/* Prepare for reading the body. */
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padder->bytes_to_copy = padder->ac3_frame_size - AC3P_AC3_HEADER_SIZE;
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padder->state = AC3P_STATE_CONTENT;
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}
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break;
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case AC3P_STATE_CONTENT:
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if (padder->bytes_to_copy > 0) {
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/* Copy one byte. */
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*(padder->out_ptr) = *(padder->in_ptr);
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ac3p_in_fw(padder);
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ac3p_out_fw(padder);
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}
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else {
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guint16 *ptr, i;
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/* Frame ready. Prepare for output: */
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/* Zero the non AC3 portion of the padded frame. */
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memset(&(padder->frame.sync_byte1) + padder->ac3_frame_size, 0,
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AC3P_IEC_FRAME_SIZE - AC3P_IEC_HEADER_SIZE - padder->ac3_frame_size);
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/* Fix the byte order in the AC3 portion: */
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ptr = (guint16 *) &(padder->frame.sync_byte1);
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i = padder->ac3_frame_size / 2;
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while (i > 0) {
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*ptr = GUINT16_TO_BE(*ptr);
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ptr++;
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i--;
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}
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/* Start over again. */
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padder->state = AC3P_STATE_SYNC1;
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return AC3P_EVENT_FRAME;
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}
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break;
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}
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}
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return AC3P_EVENT_PUSH;
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}
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