drivers/media/pci/ttpci/dvb_filter.c

// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/string.h>
#include "dvb_filter.h"

static u32 freq[4] = {480, 441, 320, 0};

static unsigned int ac3_bitrates[32] =
    {32,40,48,56,64,80,96,112,128,160,192,224,256,320,384,448,512,576,640,
     0,0,0,0,0,0,0,0,0,0,0,0,0};

static u32 ac3_frames[3][32] =
    {{64,80,96,112,128,160,192,224,256,320,384,448,512,640,768,896,1024,
      1152,1280,0,0,0,0,0,0,0,0,0,0,0,0,0},
     {69,87,104,121,139,174,208,243,278,348,417,487,557,696,835,975,1114,
      1253,1393,0,0,0,0,0,0,0,0,0,0,0,0,0},
     {96,120,144,168,192,240,288,336,384,480,576,672,768,960,1152,1344,
      1536,1728,1920,0,0,0,0,0,0,0,0,0,0,0,0,0}};

int dvb_filter_get_ac3info(u8 *mbuf, int count, struct dvb_audio_info *ai, int pr)
{
	u8 *headr;
	int found = 0;
	int c = 0;
	u8 frame = 0;
	int fr = 0;

	while ( !found  && c < count){
		u8 *b = mbuf+c;

		if ( b[0] == 0x0b &&  b[1] == 0x77 )
			found = 1;
		else {
			c++;
		}
	}

	if (!found) return -1;
	if (pr)
		printk(KERN_DEBUG "Audiostream: AC3");

	ai->off = c;
	if (c+5 >= count) return -1;

	ai->layer = 0;  // 0 for AC3
	headr = mbuf+c+2;

	frame = (headr[2]&0x3f);
	ai->bit_rate = ac3_bitrates[frame >> 1]*1000;

	if (pr)
		printk(KERN_CONT "  BRate: %d kb/s", (int) ai->bit_rate/1000);

	ai->frequency = (headr[2] & 0xc0 ) >> 6;
	fr = (headr[2] & 0xc0 ) >> 6;
	ai->frequency = freq[fr]*100;
	if (pr)
		printk(KERN_CONT "  Freq: %d Hz\n", (int) ai->frequency);

	ai->framesize = ac3_frames[fr][frame >> 1];
	if ((frame & 1) &&  (fr == 1)) ai->framesize++;
	ai->framesize = ai->framesize << 1;
	if (pr)
		printk(KERN_DEBUG "  Framesize %d\n", (int) ai->framesize);

	return 0;
}

void dvb_filter_pes2ts_init(struct dvb_filter_pes2ts *p2ts, unsigned short pid,
			    dvb_filter_pes2ts_cb_t *cb, void *priv)
{
	unsigned char *buf=p2ts->buf;

	buf[0]=0x47;
	buf[1]=(pid>>8);
	buf[2]=pid&0xff;
	p2ts->cc=0;
	p2ts->cb=cb;
	p2ts->priv=priv;
}

int dvb_filter_pes2ts(struct dvb_filter_pes2ts *p2ts, unsigned char *pes,
		      int len, int payload_start)
{
	unsigned char *buf=p2ts->buf;
	int ret=0, rest;

	//len=6+((pes[4]<<8)|pes[5]);

	if (payload_start)
		buf[1]|=0x40;
	else
		buf[1]&=~0x40;
	while (len>=184) {
		buf[3]=0x10|((p2ts->cc++)&0x0f);
		memcpy(buf+4, pes, 184);
		if ((ret=p2ts->cb(p2ts->priv, buf)))
			return ret;
		len-=184; pes+=184;
		buf[1]&=~0x40;
	}
	if (!len)
		return 0;
	buf[3]=0x30|((p2ts->cc++)&0x0f);
	rest=183-len;
	if (rest) {
		buf[5]=0x00;
		if (rest-1)
			memset(buf+6, 0xff, rest-1);
	}
	buf[4]=rest;
	memcpy(buf+5+rest, pes, len);
	return p2ts->cb(p2ts->priv, buf);
}