mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
synced 2024-12-24 09:10:36 +00:00
254 lines
7.4 KiB
C
254 lines
7.4 KiB
C
/* GStreamer
|
|
* Copyright (C) 2003 Martin Soto <martinsoto@users.sourceforge.net>
|
|
*
|
|
* ac3_padder.c: Pad AC3 frames for use with an SPDIF interface.
|
|
*
|
|
* This library is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Library General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2 of the License, or (at your option) any later version.
|
|
*
|
|
* This library is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* Library General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Library General Public
|
|
* License along with this library; if not, write to the
|
|
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
|
|
* Boston, MA 02110-1301, USA.
|
|
*/
|
|
|
|
#ifdef HAVE_CONFIG_H
|
|
#include "config.h"
|
|
#endif
|
|
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
|
|
#include "ac3_padder.h"
|
|
|
|
#define IEC61937_DATA_TYPE_AC3 1
|
|
|
|
struct frmsize_s
|
|
{
|
|
unsigned short bit_rate;
|
|
unsigned short frm_size[3];
|
|
};
|
|
|
|
|
|
static const struct frmsize_s frmsizecod_tbl[64] = {
|
|
{32, {64, 69, 96}},
|
|
{32, {64, 70, 96}},
|
|
{40, {80, 87, 120}},
|
|
{40, {80, 88, 120}},
|
|
{48, {96, 104, 144}},
|
|
{48, {96, 105, 144}},
|
|
{56, {112, 121, 168}},
|
|
{56, {112, 122, 168}},
|
|
{64, {128, 139, 192}},
|
|
{64, {128, 140, 192}},
|
|
{80, {160, 174, 240}},
|
|
{80, {160, 175, 240}},
|
|
{96, {192, 208, 288}},
|
|
{96, {192, 209, 288}},
|
|
{112, {224, 243, 336}},
|
|
{112, {224, 244, 336}},
|
|
{128, {256, 278, 384}},
|
|
{128, {256, 279, 384}},
|
|
{160, {320, 348, 480}},
|
|
{160, {320, 349, 480}},
|
|
{192, {384, 417, 576}},
|
|
{192, {384, 418, 576}},
|
|
{224, {448, 487, 672}},
|
|
{224, {448, 488, 672}},
|
|
{256, {512, 557, 768}},
|
|
{256, {512, 558, 768}},
|
|
{320, {640, 696, 960}},
|
|
{320, {640, 697, 960}},
|
|
{384, {768, 835, 1152}},
|
|
{384, {768, 836, 1152}},
|
|
{448, {896, 975, 1344}},
|
|
{448, {896, 976, 1344}},
|
|
{512, {1024, 1114, 1536}},
|
|
{512, {1024, 1115, 1536}},
|
|
{576, {1152, 1253, 1728}},
|
|
{576, {1152, 1254, 1728}},
|
|
{640, {1280, 1393, 1920}},
|
|
{640, {1280, 1394, 1920}}
|
|
};
|
|
|
|
|
|
|
|
/* Go one byte forward in the input buffer. */
|
|
#define ac3p_in_fw(padder) ((padder)->in_ptr++, (padder)->remaining--)
|
|
|
|
/* Go one byte forward in the output buffer. */
|
|
#define ac3p_out_fw(padder) ((padder)->out_ptr++, (padder)->bytes_to_copy--)
|
|
|
|
|
|
/**
|
|
* ac3p_init:
|
|
* @padder: The padder structure to initialize.
|
|
*
|
|
* Initializes an AC3 stream padder. This structure can be
|
|
* subsequently used to parse an AC3 stream and convert it to IEC958
|
|
* (S/PDIF) padded packets.
|
|
*/
|
|
extern void
|
|
ac3p_init (ac3_padder * padder)
|
|
{
|
|
const char sync[4] = { 0x72, 0xF8, 0x1F, 0x4E };
|
|
|
|
padder->state = AC3P_STATE_SYNC1;
|
|
|
|
/* No material to read yet. */
|
|
padder->remaining = 0;
|
|
|
|
/* Initialize the sync bytes in the frame. */
|
|
memcpy (padder->frame.header, sync, 4);
|
|
}
|
|
|
|
|
|
/**
|
|
* ac3_push_data:
|
|
* @padder: The padder structure.
|
|
* @data: A pointer to a buffer with new data to parse. This should
|
|
* correspond to a new piece of a stream containing raw AC3 data.
|
|
* @size: The number of available bytes in the buffer.
|
|
*
|
|
* Pushes a new buffer of data to be parsed by the ac3 padder. The
|
|
* ac3_parse() function will actually parse the data and report when
|
|
* new frames are found. This funcion should only be called once at
|
|
* the beginning of the parsing process, or when the ac3_parse()
|
|
* function returns the %AC3P_EVENT_PUSH event.
|
|
*/
|
|
extern void
|
|
ac3p_push_data (ac3_padder * padder, guchar * data, guint size)
|
|
{
|
|
padder->in_ptr = data;
|
|
padder->remaining = size;
|
|
}
|
|
|
|
|
|
/**
|
|
* ac3p_parse:
|
|
* @padder: The padder structure.
|
|
*
|
|
* Parses the bytes already pushed into the padder structure (see
|
|
* ac3p_push_data()) and returns an event value depending on the
|
|
* results of the parsing.
|
|
*
|
|
* Returns: %AC3P_EVENT_FRAME to indicate that a new AC3 was found and
|
|
* padded for IEC958 transmission. This frame can be read inmediatly
|
|
* with ac3p_frame(). %AC3P_EVENT_PUSH to indicate that new data from
|
|
* the input stream must be pushed into the padder using
|
|
* ac3p_push_data(). This function should be called again after
|
|
* pushing the data.
|
|
*/
|
|
extern int
|
|
ac3p_parse (ac3_padder * padder)
|
|
{
|
|
while (padder->remaining > 0) {
|
|
switch (padder->state) {
|
|
case AC3P_STATE_SYNC1:
|
|
if (*(padder->in_ptr) == 0x0b) {
|
|
/* The first sync byte was found. Go to the next state. */
|
|
padder->frame.sync_byte1 = 0x0b;
|
|
padder->state = AC3P_STATE_SYNC2;
|
|
}
|
|
ac3p_in_fw (padder);
|
|
break;
|
|
|
|
case AC3P_STATE_SYNC2:
|
|
if (*(padder->in_ptr) == 0x77) {
|
|
/* The second sync byte was seen right after the first. Go to
|
|
the next state. */
|
|
padder->frame.sync_byte2 = 0x77;
|
|
padder->state = AC3P_STATE_HEADER;
|
|
|
|
/* Skip one byte. */
|
|
ac3p_in_fw (padder);
|
|
|
|
/* Prepare for reading the header. */
|
|
padder->out_ptr = (guchar *) & (padder->frame.crc1);
|
|
/* Discount the 2 sync bytes from the header size. */
|
|
padder->bytes_to_copy = AC3P_AC3_HEADER_SIZE - 2;
|
|
} else {
|
|
/* The second sync byte was not seen. Go back to the
|
|
first state. */
|
|
padder->state = AC3P_STATE_SYNC1;
|
|
}
|
|
break;
|
|
|
|
case AC3P_STATE_HEADER:
|
|
if (padder->bytes_to_copy > 0) {
|
|
/* Copy one byte. */
|
|
*(padder->out_ptr) = *(padder->in_ptr);
|
|
ac3p_in_fw (padder);
|
|
ac3p_out_fw (padder);
|
|
} else {
|
|
int fscod;
|
|
|
|
/* The header is ready: */
|
|
|
|
fscod = (padder->frame.code >> 6) & 0x03;
|
|
|
|
/* Calculate the frame size. */
|
|
padder->ac3_frame_size =
|
|
2 * frmsizecod_tbl[padder->frame.code & 0x3f].frm_size[fscod];
|
|
|
|
/* Set up the IEC header. */
|
|
if (padder->ac3_frame_size > 0) {
|
|
padder->frame.header[4] = IEC61937_DATA_TYPE_AC3;
|
|
} else {
|
|
/* Don't know what it is, better be careful. */
|
|
padder->state = AC3P_STATE_SYNC1;
|
|
break;
|
|
}
|
|
padder->frame.header[5] = 0x00;
|
|
padder->frame.header[6] = (padder->ac3_frame_size * 8) & 0xFF;
|
|
padder->frame.header[7] = ((padder->ac3_frame_size * 8) >> 8) & 0xFF;
|
|
|
|
/* Prepare for reading the body. */
|
|
padder->bytes_to_copy = padder->ac3_frame_size - AC3P_AC3_HEADER_SIZE;
|
|
padder->state = AC3P_STATE_CONTENT;
|
|
}
|
|
break;
|
|
|
|
case AC3P_STATE_CONTENT:
|
|
if (padder->bytes_to_copy > 0) {
|
|
/* Copy one byte. */
|
|
*(padder->out_ptr) = *(padder->in_ptr);
|
|
ac3p_in_fw (padder);
|
|
ac3p_out_fw (padder);
|
|
} else {
|
|
guint16 *ptr, i;
|
|
|
|
/* Frame ready. Prepare for output: */
|
|
|
|
/* Zero the non AC3 portion of the padded frame. */
|
|
memset (&(padder->frame.sync_byte1) + padder->ac3_frame_size, 0,
|
|
AC3P_IEC_FRAME_SIZE - AC3P_IEC_HEADER_SIZE -
|
|
padder->ac3_frame_size);
|
|
|
|
/* Fix the byte order in the AC3 portion: */
|
|
ptr = (guint16 *) & (padder->frame.sync_byte1);
|
|
i = padder->ac3_frame_size / 2;
|
|
while (i > 0) {
|
|
*ptr = GUINT16_TO_BE (*ptr);
|
|
ptr++;
|
|
i--;
|
|
}
|
|
|
|
/* Start over again. */
|
|
padder->state = AC3P_STATE_SYNC1;
|
|
|
|
return AC3P_EVENT_FRAME;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
|
|
return AC3P_EVENT_PUSH;
|
|
}
|