AuxXxilium/linux_dsm_epyc7002
1
0
Fork 0
mirror of https://github.com/AuxXxilium/linux_dsm_epyc7002.git synced 2024-12-28 10:45:23 +07:00
Code Issues Actions Packages Projects Releases Wiki Activity

media: vidtv: add a poor guy's simulation to preBER stats

Browse Source 
A typical digital TV stream has errors that are corrected
by Viterbi. While the error rate after Viterbi is usually
zero, with good signals, there are some chances of getting
random errors before that, which are auto-corrected by
the error code algorithm.

Add a poor guy's implementation that would show some
noise at the pre-BER part of the demod.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
This commit is contained in:
Mauro Carvalho Chehab 2020-09-15 10:06:52 +02:00
parent 2cf846b1f3
commit 82d00a1a2a
1 changed files with 21 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
drivers/media/test-drivers/vidtv/vidtv_mux.c
View File

@ -21,6 +21,7 @@
#include <linux/delay.h>
#include <linux/vmalloc.h>
#include <linux/math64.h>
#include "vidtv_mux.h"
#include "vidtv_ts.h"
#include "vidtv_pes.h"
@ -376,6 +377,7 @@ static void vidtv_mux_clear(struct vidtv_mux *m)
m->mux_buf_offset = 0;
}
#define ERR_RATE 10000000
static void vidtv_mux_tick(struct work_struct *work)
{
struct vidtv_mux *m = container_of(work,
@ -384,6 +386,7 @@ static void vidtv_mux_tick(struct work_struct *work)
struct dtv_frontend_properties *c = &m->fe->dtv_property_cache;
u32 nbytes;
u32 npkts;
u32 tot_bits = 0;
while (m->streaming) {
nbytes = 0;
@ -419,10 +422,26 @@ static void vidtv_mux_tick(struct work_struct *work)
* but post BER count can be lower than pre BER, if the error
* correction logic discards packages.
*/
c->pre_bit_count.stat[0].uvalue = nbytes;
c->post_bit_count.stat[0].uvalue = nbytes;
c->pre_bit_count.stat[0].uvalue = nbytes * 8;
c->post_bit_count.stat[0].uvalue = nbytes * 8;
c->block_count.stat[0].uvalue += npkts;
/*
* Even without any visible errors for the user, the pre-BER
* stats usually have an error range up to 1E-6. So,
* add some random error increment count to it.
*
* Please notice that this is a poor guy's implementation,
* as it will produce one corrected bit error every time
* ceil(total bytes / ERR_RATE) is incremented, without
* any sort of (pseudo-)randomness.
*/
tot_bits += nbytes * 8;
if (tot_bits > ERR_RATE) {
c->pre_bit_error.stat[0].uvalue++;
tot_bits -= ERR_RATE;
}
usleep_range(VIDTV_SLEEP_USECS, VIDTV_MAX_SLEEP_USECS);
}
}