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90d4598207
Original commit message from CVS: * gst/iec958/ac3_padder.c: (ac3p_parse): * gst/iec958/ac3_padder.h: * gst/iec958/ac3iec.c: (ac3iec_init), (ac3iec_set_property), (ac3iec_chain_raw), (ac3iec_change_state): * gst/iec958/ac3iec.h: Write rate into the caps, for the allowed ac3 rates. Some minor cleanups.
394 lines
13 KiB
C
394 lines
13 KiB
C
/* GStreamer
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* Copyright (C) 2003, 2004 Martin Soto <martinsoto@users.sourceforge.net>
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* 2005 Michael Smith <msmith@fluendo.com>
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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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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[] = {
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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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static const guint16 ac3_crc_lut[256] = {
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0x0000, 0x8005, 0x800f, 0x000a, 0x801b, 0x001e, 0x0014, 0x8011,
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0x8033, 0x0036, 0x003c, 0x8039, 0x0028, 0x802d, 0x8027, 0x0022,
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0x8063, 0x0066, 0x006c, 0x8069, 0x0078, 0x807d, 0x8077, 0x0072,
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0x0050, 0x8055, 0x805f, 0x005a, 0x804b, 0x004e, 0x0044, 0x8041,
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0x80c3, 0x00c6, 0x00cc, 0x80c9, 0x00d8, 0x80dd, 0x80d7, 0x00d2,
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0x00f0, 0x80f5, 0x80ff, 0x00fa, 0x80eb, 0x00ee, 0x00e4, 0x80e1,
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0x00a0, 0x80a5, 0x80af, 0x00aa, 0x80bb, 0x00be, 0x00b4, 0x80b1,
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0x8093, 0x0096, 0x009c, 0x8099, 0x0088, 0x808d, 0x8087, 0x0082,
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0x8183, 0x0186, 0x018c, 0x8189, 0x0198, 0x819d, 0x8197, 0x0192,
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0x01b0, 0x81b5, 0x81bf, 0x01ba, 0x81ab, 0x01ae, 0x01a4, 0x81a1,
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0x01e0, 0x81e5, 0x81ef, 0x01ea, 0x81fb, 0x01fe, 0x01f4, 0x81f1,
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0x81d3, 0x01d6, 0x01dc, 0x81d9, 0x01c8, 0x81cd, 0x81c7, 0x01c2,
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0x0140, 0x8145, 0x814f, 0x014a, 0x815b, 0x015e, 0x0154, 0x8151,
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0x8173, 0x0176, 0x017c, 0x8179, 0x0168, 0x816d, 0x8167, 0x0162,
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0x8123, 0x0126, 0x012c, 0x8129, 0x0138, 0x813d, 0x8137, 0x0132,
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0x0110, 0x8115, 0x811f, 0x011a, 0x810b, 0x010e, 0x0104, 0x8101,
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0x8303, 0x0306, 0x030c, 0x8309, 0x0318, 0x831d, 0x8317, 0x0312,
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0x0330, 0x8335, 0x833f, 0x033a, 0x832b, 0x032e, 0x0324, 0x8321,
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0x0360, 0x8365, 0x836f, 0x036a, 0x837b, 0x037e, 0x0374, 0x8371,
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0x8353, 0x0356, 0x035c, 0x8359, 0x0348, 0x834d, 0x8347, 0x0342,
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0x03c0, 0x83c5, 0x83cf, 0x03ca, 0x83db, 0x03de, 0x03d4, 0x83d1,
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0x83f3, 0x03f6, 0x03fc, 0x83f9, 0x03e8, 0x83ed, 0x83e7, 0x03e2,
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0x83a3, 0x03a6, 0x03ac, 0x83a9, 0x03b8, 0x83bd, 0x83b7, 0x03b2,
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0x0390, 0x8395, 0x839f, 0x039a, 0x838b, 0x038e, 0x0384, 0x8381,
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0x0280, 0x8285, 0x828f, 0x028a, 0x829b, 0x029e, 0x0294, 0x8291,
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0x82b3, 0x02b6, 0x02bc, 0x82b9, 0x02a8, 0x82ad, 0x82a7, 0x02a2,
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0x82e3, 0x02e6, 0x02ec, 0x82e9, 0x02f8, 0x82fd, 0x82f7, 0x02f2,
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0x02d0, 0x82d5, 0x82df, 0x02da, 0x82cb, 0x02ce, 0x02c4, 0x82c1,
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0x8243, 0x0246, 0x024c, 0x8249, 0x0258, 0x825d, 0x8257, 0x0252,
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0x0270, 0x8275, 0x827f, 0x027a, 0x826b, 0x026e, 0x0264, 0x8261,
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0x0220, 0x8225, 0x822f, 0x022a, 0x823b, 0x023e, 0x0234, 0x8231,
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0x8213, 0x0216, 0x021c, 0x8219, 0x0208, 0x820d, 0x8207, 0x0202
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};
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static gint ac3_sample_rates[] = { 48000, 44100, 32000, -1 };
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typedef guint16 ac3_crc_state;
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static void
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ac3_crc_init (ac3_crc_state * state)
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{
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*state = 0;
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}
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static void
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ac3_crc_update (ac3_crc_state * state, guint8 * data, guint32 num_bytes)
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{
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int i;
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for (i = 0; i < num_bytes; i++)
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*state = ac3_crc_lut[data[i] ^ (*state >> 8)] ^ (*state << 8);
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}
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static int
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ac3_crc_validate (ac3_crc_state * state)
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{
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return (*state == 0);
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}
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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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void
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ac3p_init (ac3_padder * padder)
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{
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const char sync[4] = { 0xF8, 0x72, 0x4E, 0x1F };
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padder->state = AC3P_STATE_SYNC1;
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padder->skipped = 0;
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/* No material to read yet. */
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padder->buffer = NULL;
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padder->buffer_end = 0;
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padder->buffer_cur = 0;
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padder->buffer_size = 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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void
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ac3p_clear (ac3_padder * padder)
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{
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g_free (padder->buffer);
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}
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static void
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resync (ac3_padder * padder, int offset, int skipped)
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{
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padder->buffer_cur -= offset;
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padder->state = AC3P_STATE_SYNC1;
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padder->skipped += skipped;
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/* We don't want our buffer to grow unboundedly if we fail to find sync, but
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* nor do we want to do this every time we call resync() */
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if (padder->buffer_cur > 4096) {
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memmove (padder->buffer, padder->buffer + padder->buffer_cur,
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padder->buffer_end - padder->buffer_cur);
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padder->buffer_end -= padder->buffer_cur;
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padder->buffer_cur = 0;
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}
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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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if (padder->buffer_end + size > padder->buffer_size) {
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padder->buffer_size = padder->buffer_end + size;
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padder->buffer = g_realloc (padder->buffer, padder->buffer_size);
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}
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memcpy (padder->buffer + padder->buffer_end, data, size);
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padder->buffer_end += 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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* Note that the returned data (which naturally comes in 16 bit sub-frames) is
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* big-endian, and may need to be byte-swapped for little-endian output.
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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->buffer_cur < padder->buffer_end) {
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switch (padder->state) {
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case AC3P_STATE_SYNC1:
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if (padder->buffer[padder->buffer_cur++] == 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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} else
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resync (padder, 0, 1);
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break;
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case AC3P_STATE_SYNC2:
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if (padder->buffer[padder->buffer_cur++] == 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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/* 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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} 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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resync (padder, 0, 2);
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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->buffer[padder->buffer_cur++];
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padder->bytes_to_copy--;
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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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/* fscod == 3 is a reserved code, we're not meant to do playback in
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* this case. frmsizecod being out-of-range (there are 38 entries)
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* doesn't appear to be well-defined, but treat the same.
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* The likely cause of both of these is false sync, so skip back to
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* just in front of the previous sync word and start looking again.
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*/
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if (fscod == 3 || (padder->frame.code & 0x3f) >= 38) {
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resync (padder, AC3P_AC3_HEADER_SIZE - 2, 2);
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continue;
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}
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padder->rate = ac3_sample_rates[fscod];
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/* Calculate the frame size (in 16 bit units). */
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padder->ac3_frame_size =
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frmsizecod_tbl[padder->frame.code & 0x3f].frm_size[fscod];
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/* Prepare for reading the body. */
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padder->bytes_to_copy = padder->ac3_frame_size * 2
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- 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->buffer[padder->buffer_cur++];
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padder->bytes_to_copy--;
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} else {
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int framesize;
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int crclen1, crclen2;
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guint8 *tmp;
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ac3_crc_state state;
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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 * 2, 0,
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AC3P_IEC_FRAME_SIZE - AC3P_IEC_HEADER_SIZE -
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padder->ac3_frame_size * 2);
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/* Now checking the two CRCs. If either fails, then we re-feed all
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* the data starting immediately after the 16-bit syncword (which we
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* can now assume was a false sync) */
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/* Length of CRC1 is defined as
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truncate(framesize/2) + truncate(framesize/8)
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units (each of which is 16 bit, as is 'framesize'), but this
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includes the syncword, which is NOT calculated as part of
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the CRC.
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*/
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framesize = padder->ac3_frame_size;
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crclen1 = (framesize / 2 + framesize / 8) * 2 - 2;
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tmp = (guint8 *) (&(padder->frame.crc1));
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ac3_crc_init (&state);
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ac3_crc_update (&state, tmp, crclen1);
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if (!ac3_crc_validate (&state)) {
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/* Rewind current stream pointer to immediately following the last
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* attempted sync point, then continue parsing in initial state */
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resync (padder, padder->ac3_frame_size - 2, 2);
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continue;
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}
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/* Now check CRC2, which covers the entire frame other than the
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* 16-bit syncword */
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crclen2 = padder->ac3_frame_size * 2 - 2;
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ac3_crc_init (&state);
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ac3_crc_update (&state, tmp, crclen2);
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if (!ac3_crc_validate (&state)) {
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/* Rewind current stream pointer to immediately following the last
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* attempted sync point, then continue parsing in initial state */
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resync (padder, padder->ac3_frame_size - 2, 2);
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continue;
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}
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/* Now set up the rest of the IEC header (we already filled in the
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32 bit sync word. */
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/* Byte 5 has:
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bits 0-4: data type dependent. For AC3, the bottom 3 of these bits
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are copied from the AC3 frame (bsmod value), the top 2
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bits are reserved, and set to zero.
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bits 5-7: data stream number. We only do one data stream, so it's
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zero.
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*/
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padder->frame.header[4] = padder->frame.bsidmod & 0x07;
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/* Byte 6:
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bits 0-4: data type. 1 for AC3.
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bits 5-6: reserved, zero.
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bit 7: error_flag. Zero if frame contains no errors
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*/
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padder->frame.header[5] = 1; /* AC3 is defined as datatype 1 */
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/* Now, 16 bit frame size, in bits. */
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padder->frame.header[6] = ((padder->ac3_frame_size * 16) >> 8) & 0xFF;
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padder->frame.header[7] = (padder->ac3_frame_size * 16) & 0xFF;
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/* We're done, reset state and signal that we have a frame */
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padder->skipped = 0;
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padder->state = AC3P_STATE_SYNC1;
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memmove (padder->buffer, padder->buffer + padder->buffer_cur,
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padder->buffer_end - padder->buffer_cur);
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padder->buffer_end -= padder->buffer_cur;
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padder->buffer_cur = 0;
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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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