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[media] gspca_sonixb: Rewrite start of frame detection

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Our old start of frame detection code wrongly assumes that the sof
marker always lives at the beginning of the frame. At least for the
0c45:602a camera this is not the case. This patch also improves
the framerate from 28 fps to 30 fps with the 0c45:6005 and 0c45:6007

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Hans de Goede 2010-12-12 08:55:04 -03:00 committed by Mauro Carvalho Chehab
parent d6746d55da
commit 2b3e284a89
1 changed files with 106 additions and 54 deletions
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160
drivers/media/video/gspca/sonixb.c
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@ -56,6 +56,8 @@ struct sd {
int prev_avg_lum;
int exp_too_low_cnt;
int exp_too_high_cnt;
int header_read;
u8 header[12]; /* Header without sof marker */
unsigned short exposure;
unsigned char gain;
@ -1177,13 +1179,10 @@ static void sd_stopN(struct gspca_dev *gspca_dev)
sd_init(gspca_dev);
}
static void sd_pkt_scan(struct gspca_dev *gspca_dev,
u8 *data, /* isoc packet */
int len) /* iso packet length */
static u8* find_sof(struct gspca_dev *gspca_dev, u8 *data, int len)
{
int i;
struct sd *sd = (struct sd *) gspca_dev;
struct cam *cam = &gspca_dev->cam;
int i, header_size = (sd->bridge == BRIDGE_103) ? 18 : 12;
/* frames start with:
* ff ff 00 c4 c4 96 synchro
@ -1194,58 +1193,84 @@ static void sd_pkt_scan(struct gspca_dev *gspca_dev,
* ll mm brightness sum outside auto exposure
* (xx xx xx xx xx) audio values for snc103
*/
if (len > 6 && len < 24) {
for (i = 0; i < len - 6; i++) {
if (data[0 + i] == 0xff
&& data[1 + i] == 0xff
&& data[2 + i] == 0x00
&& data[3 + i] == 0xc4
&& data[4 + i] == 0xc4
&& data[5 + i] == 0x96) { /* start of frame */
int lum = -1;
int pkt_type = LAST_PACKET;
int fr_h_sz = (sd->bridge == BRIDGE_103) ?
18 : 12;
if (len - i < fr_h_sz) {
PDEBUG(D_STREAM, "packet too short to"
" get avg brightness");
} else if (sd->bridge == BRIDGE_103) {
lum = data[i + 9] +
(data[i + 10] << 8);
} else {
lum = data[i + 8] + (data[i + 9] << 8);
}
/* When exposure changes midway a frame we
get a lum of 0 in this case drop 2 frames
as the frames directly after an exposure
change have an unstable image. Sometimes lum
*really* is 0 (cam used in low light with
low exposure setting), so do not drop frames
if the previous lum was 0 too. */
if (lum == 0 && sd->prev_avg_lum != 0) {
lum = -1;
sd->frames_to_drop = 2;
sd->prev_avg_lum = 0;
} else
sd->prev_avg_lum = lum;
atomic_set(&sd->avg_lum, lum);
if (sd->frames_to_drop) {
sd->frames_to_drop--;
pkt_type = DISCARD_PACKET;
}
gspca_frame_add(gspca_dev, pkt_type,
NULL, 0);
data += i + fr_h_sz;
len -= i + fr_h_sz;
gspca_frame_add(gspca_dev, FIRST_PACKET,
data, len);
return;
for (i = 0; i < len; i++) {
switch (sd->header_read) {
case 0:
if (data[i] == 0xff)
sd->header_read++;
break;
case 1:
if (data[i] == 0xff)
sd->header_read++;
else
sd->header_read = 0;
break;
case 2:
if (data[i] == 0x00)
sd->header_read++;
else if (data[i] != 0xff)
sd->header_read = 0;
break;
case 3:
if (data[i] == 0xc4)
sd->header_read++;
else if (data[i] == 0xff)
sd->header_read = 1;
else
sd->header_read = 0;
break;
case 4:
if (data[i] == 0xc4)
sd->header_read++;
else if (data[i] == 0xff)
sd->header_read = 1;
else
sd->header_read = 0;
break;
case 5:
if (data[i] == 0x96)
sd->header_read++;
else if (data[i] == 0xff)
sd->header_read = 1;
else
sd->header_read = 0;
break;
default:
sd->header[sd->header_read - 6] = data[i];
sd->header_read++;
if (sd->header_read == header_size) {
sd->header_read = 0;
return data + i + 1;
}
}
}
return NULL;
}
static void sd_pkt_scan(struct gspca_dev *gspca_dev,
u8 *data, /* isoc packet */
int len) /* iso packet length */
{
int fr_h_sz = 0, lum_offset = 0, len_after_sof = 0;
struct sd *sd = (struct sd *) gspca_dev;
struct cam *cam = &gspca_dev->cam;
u8 *sof;
sof = find_sof(gspca_dev, data, len);
if (sof) {
if (sd->bridge == BRIDGE_103) {
fr_h_sz = 18;
lum_offset = 3;
} else {
fr_h_sz = 12;
lum_offset = 2;
}
len_after_sof = len - (sof - data);
len = (sof - data) - fr_h_sz;
if (len < 0)
len = 0;
}
if (cam->cam_mode[gspca_dev->curr_mode].priv & MODE_RAW) {
/* In raw mode we sometimes get some garbage after the frame
@ -1259,6 +1284,33 @@ static void sd_pkt_scan(struct gspca_dev *gspca_dev,
}
gspca_frame_add(gspca_dev, INTER_PACKET, data, len);
if (sof) {
int lum = sd->header[lum_offset] +
(sd->header[lum_offset + 1] << 8);
/* When exposure changes midway a frame we
get a lum of 0 in this case drop 2 frames
as the frames directly after an exposure
change have an unstable image. Sometimes lum
*really* is 0 (cam used in low light with
low exposure setting), so do not drop frames
if the previous lum was 0 too. */
if (lum == 0 && sd->prev_avg_lum != 0) {
lum = -1;
sd->frames_to_drop = 2;
sd->prev_avg_lum = 0;
} else
sd->prev_avg_lum = lum;
atomic_set(&sd->avg_lum, lum);
if (sd->frames_to_drop)
sd->frames_to_drop--;
else
gspca_frame_add(gspca_dev, LAST_PACKET, NULL, 0);
gspca_frame_add(gspca_dev, FIRST_PACKET, sof, len_after_sof);
}
}
static int sd_setbrightness(struct gspca_dev *gspca_dev, __s32 val)