From 2c98438c994b119256ded007808f153a4a5b6f6a Mon Sep 17 00:00:00 2001 From: "Ronald S. Bultje" Date: Thu, 29 May 2003 14:35:24 +0000 Subject: I'm too lazy to comment this Original commit message from CVS: New dxr3 plugins from Martin Soto --- sys/dxr3/ac3_padder.c | 255 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 255 insertions(+) create mode 100644 sys/dxr3/ac3_padder.c (limited to 'sys/dxr3/ac3_padder.c') diff --git a/sys/dxr3/ac3_padder.c b/sys/dxr3/ac3_padder.c new file mode 100644 index 00000000..f6ff270b --- /dev/null +++ b/sys/dxr3/ac3_padder.c @@ -0,0 +1,255 @@ +/* GStreamer + * Copyright (C) 2003 Martin Soto + * + * 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., 59 Temple Place - Suite 330, + * Boston, MA 02111-1307, USA. + */ + +#include +#include + +#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; +} + -- cgit v1.2.1