Re: About the VIDIOC_DQBUF
Hi,
Sorry I still don't get what the full frame means, but I might
consider that is the maximum resolution-ed image data coming from
external camera module. And whatever it is, you might have no problem
getting data through memcpy with buf.byteused size.
Cheers,
Nate
On Tue, Jun 9, 2009 at 11:22 AM, xieyili@gmail.com wrote:
hi ~~ Dongsoo, Nathaniel ~
I am sorry for disturbing you, and not descripe the question clear ~
Thanks very much for your help ~~
I know that I must stop preview with streamoff and re-configure with
s_fmt ~~ I have asked to you before ~!~
The full frame means a complete frame ~Because I just need to get the
frame data and post it to multimedia framework, so I want to consult to
you that if I can get a complete frame with memcpy ~~
I want to know that can I get a complete frame from buf.start to the
end , and the memory-lenth is buf.byteused ~
buf.byteused
|-|
buf.startend
在 2009-06-08一的 20:40 +0900，Dongsoo, Nathaniel Kim写道：
Hi,
Sorry I'm not an expert, you can expect expertise from maintainers not from
me.
But before answering your question about capturing, I'm not sure about
what the full frame means. I just assume that you meant to say the
biggest resolution of image frame, right?
So, when you are to capture a full resolution data while preview is
working, you need to stop preview with streamoff, re-configure
resolution with s_fmt to external camera module and start capturing
issuing streamon with re-configured resolution. I think you are
well-aware with this, aren't you? And in my opinion, memcpy may be
cool for that. What else are you expecting to use? and for what?
Anyway, I wish you luck.
Cheers,
Nate
On Mon, Jun 8, 2009 at 5:02 PM, xieyili@gmail.com wrote:
Hi Dongsoo, Nathaniel ~
You must be expert on V4l2 ~ Thanks very much for your help and advice
~!~
I used the MXC camera interface driver from Fressscale ,I readed the
driver interface just now ,and have fouded that the driver not modified
the buf.lenth but buf.byteused . You are very right , I will use the
buf.byteused instead of buf.length ~
There is also a problem I want to consult to you ~ Can i get a full
frame with the below method if the driver have no problem ?
memcpy((mCameraProwave-getPreviewHeap())-base(),
v4l2Buffer[buf.index].start, buf.byteused) ;
Because I just need to implement a hal for getting the frame data and
post it to top layer , so I used the memcpy simply . Am I right ~ ? Or
what about your advice ?
Thanks a lot ~~
在 2009-06-08一的 15:56 +0900，Dongsoo, Nathaniel Kim写道：
Hello Xie,
I'm not sure which camera interface driver you are using, but it seems
to be camera interface driver's problem. Let me guess, are you using
pxa camera interface driver from Marvell?(proprietary but not in up
stream kernel)
It just looks like that camera interface driver is not returning
proper data in dqbuf.
And one more thing. I prefer to use byteused rather than length in
buf. because as far as I know the size of preview data from camera is
in byte unit which we need to copy to memory. But it should be
possible to use length, I guess..
Cheers,
Nate
On Mon, Jun 8, 2009 at 11:05 AM, xieyili@gmail.com wrote:
Dear all ~~
I have met a issue when I used the mmap method for previewing . I just
used the standard code as spec to get the image data :
status_t CameraHardwareProwave::V4l2Camera::v4l2CaptureMainloop()
{
LOG_FUNCTION_NAME
int rt ;
unsigned int i ;
fd_set fds ;
struct timeval tv ;
struct v4l2_buffer buf ;
for(;;){
FD_ZERO(fds) ;
FD_SET(v4l2Fd, fds) ;
//now the time is long ,just for debug
tv.tv_sec = 2 ;
tv.tv_usec = 0 ;
rt = select(v4l2Fd + 1, fds, NULL, NULL, tv) ;
LOGD(The value of select return : %d\n, rt) ;
/** for debug
if(V4L2_NOERROR != v4l2ReadFrame()){
LOGE(READ ERROR) ;
}
***/
if(-1 == rt){
LOGE(there is something wrong in select
function(select)) ;
//no defined error manage
return V4L2_IOCTL_ERROR ;
}
if(0 == rt){
LOGE(wait for data timeout in select) ;
return V4L2_TIMEOUT ;
}
memset(buf, 0, sizeof(buf)) ;
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE ;
buf.memory = V4L2_MEMORY_MMAP ;
if(-1 == ioctl(v4l2Fd, VIDIOC_DQBUF, buf)){
LOGE(there is something wrong in dequeue
Re: About the VIDIOC_DQBUF
hi ~~
I have found the problem ~~ The 3'rd partner didn't give us the right
v4l2 driver. Thanks for your help ~~
Best wishes
在 2009-06-09二的 16:41 +0900，Dongsoo, Nathaniel Kim写道：
Hi,
Sorry I still don't get what the full frame means, but I might
consider that is the maximum resolution-ed image data coming from
external camera module. And whatever it is, you might have no problem
getting data through memcpy with buf.byteused size.
Cheers,
Nate
On Tue, Jun 9, 2009 at 11:22 AM, xieyili@gmail.com wrote:
hi ~~ Dongsoo, Nathaniel ~
I am sorry for disturbing you, and not descripe the question clear ~
Thanks very much for your help ~~
I know that I must stop preview with streamoff and re-configure with
s_fmt ~~ I have asked to you before ~!~
The full frame means a complete frame ~Because I just need to get the
frame data and post it to multimedia framework, so I want to consult to
you that if I can get a complete frame with memcpy ~~
I want to know that can I get a complete frame from buf.start to the
end , and the memory-lenth is buf.byteused ~
buf.byteused
|-|
buf.startend
在 2009-06-08一的 20:40 +0900，Dongsoo, Nathaniel Kim写道：
Hi,
Sorry I'm not an expert, you can expect expertise from maintainers not
from me.
But before answering your question about capturing, I'm not sure about
what the full frame means. I just assume that you meant to say the
biggest resolution of image frame, right?
So, when you are to capture a full resolution data while preview is
working, you need to stop preview with streamoff, re-configure
resolution with s_fmt to external camera module and start capturing
issuing streamon with re-configured resolution. I think you are
well-aware with this, aren't you? And in my opinion, memcpy may be
cool for that. What else are you expecting to use? and for what?
Anyway, I wish you luck.
Cheers,
Nate
On Mon, Jun 8, 2009 at 5:02 PM, xieyili@gmail.com wrote:
Hi Dongsoo, Nathaniel ~
You must be expert on V4l2 ~ Thanks very much for your help and advice
~!~
I used the MXC camera interface driver from Fressscale ,I readed the
driver interface just now ,and have fouded that the driver not modified
the buf.lenth but buf.byteused . You are very right , I will use the
buf.byteused instead of buf.length ~
There is also a problem I want to consult to you ~ Can i get a full
frame with the below method if the driver have no problem ?
memcpy((mCameraProwave-getPreviewHeap())-base(),
v4l2Buffer[buf.index].start, buf.byteused) ;
Because I just need to implement a hal for getting the frame data and
post it to top layer , so I used the memcpy simply . Am I right ~ ? Or
what about your advice ?
Thanks a lot ~~
在 2009-06-08一的 15:56 +0900，Dongsoo, Nathaniel Kim写道：
Hello Xie,
I'm not sure which camera interface driver you are using, but it seems
to be camera interface driver's problem. Let me guess, are you using
pxa camera interface driver from Marvell?(proprietary but not in up
stream kernel)
It just looks like that camera interface driver is not returning
proper data in dqbuf.
And one more thing. I prefer to use byteused rather than length in
buf. because as far as I know the size of preview data from camera is
in byte unit which we need to copy to memory. But it should be
possible to use length, I guess..
Cheers,
Nate
On Mon, Jun 8, 2009 at 11:05 AM, xieyili@gmail.com wrote:
Dear all ~~
I have met a issue when I used the mmap method for previewing . I just
used the standard code as spec to get the image data :
status_t CameraHardwareProwave::V4l2Camera::v4l2CaptureMainloop()
{
LOG_FUNCTION_NAME
int rt ;
unsigned int i ;
fd_set fds ;
struct timeval tv ;
struct v4l2_buffer buf ;
for(;;){
FD_ZERO(fds) ;
FD_SET(v4l2Fd, fds) ;
//now the time is long ,just for debug
tv.tv_sec = 2 ;
tv.tv_usec = 0 ;
rt = select(v4l2Fd + 1, fds, NULL, NULL, tv) ;
LOGD(The value of select return : %d\n, rt) ;
/** for debug
if(V4L2_NOERROR != v4l2ReadFrame()){
LOGE(READ ERROR) ;
}
***/
if(-1 == rt){
LOGE(there is something wrong in select
function(select)) ;
//no defined error manage
return V4L2_IOCTL_ERROR ;
}
if(0 == rt){
LOGE(wait for data timeout in select) ;
return V4L2_TIMEOUT
Re: About the VIDIOC_DQBUF
Hello Xie,
I'm not sure which camera interface driver you are using, but it seems
to be camera interface driver's problem. Let me guess, are you using
pxa camera interface driver from Marvell?(proprietary but not in up
stream kernel)
It just looks like that camera interface driver is not returning
proper data in dqbuf.
And one more thing. I prefer to use byteused rather than length in
buf. because as far as I know the size of preview data from camera is
in byte unit which we need to copy to memory. But it should be
possible to use length, I guess..
Cheers,
Nate
On Mon, Jun 8, 2009 at 11:05 AM, xieyili@gmail.com wrote:
Dear all ~~
I have met a issue when I used the mmap method for previewing . I just
used the standard code as spec to get the image data :
status_t CameraHardwareProwave::V4l2Camera::v4l2CaptureMainloop()
{
LOG_FUNCTION_NAME
int rt ;
unsigned int i ;
fd_set fds ;
struct timeval tv ;
struct v4l2_buffer buf ;
for(;;){
FD_ZERO(fds) ;
FD_SET(v4l2Fd, fds) ;
//now the time is long ,just for debug
tv.tv_sec = 2 ;
tv.tv_usec = 0 ;
rt = select(v4l2Fd + 1, fds, NULL, NULL, tv) ;
LOGD(The value of select return : %d\n, rt) ;
/** for debug
if(V4L2_NOERROR != v4l2ReadFrame()){
LOGE(READ ERROR) ;
}
***/
if(-1 == rt){
LOGE(there is something wrong in select
function(select)) ;
//no defined error manage
return V4L2_IOCTL_ERROR ;
}
if(0 == rt){
LOGE(wait for data timeout in select) ;
return V4L2_TIMEOUT ;
}
memset(buf, 0, sizeof(buf)) ;
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE ;
buf.memory = V4L2_MEMORY_MMAP ;
if(-1 == ioctl(v4l2Fd, VIDIOC_DQBUF, buf)){
LOGE(there is something wrong in dequeue
buffer(VIDIOC_DQBUF)) ;
return V4L2_IOCTL_ERROR ;
}
assert(i n_buf) ;
LOGE(buf.index 0buf.length = %d %d \n, buf.index ,
buf.length) ;
memcpy((mCameraProwave-getPreviewHeap())-base(),
v4l2Buffer[buf.index].start, buf.length) ;
if(-1 == ioctl(v4l2Fd, VIDIOC_QBUF, buf)){
LOGE(there is something wrong in enqueue
buffer(VIDIOC_QBUF)) ;
return V4L2_IOCTL_ERROR ;
}
//break ; //i don't know whether the break is needed ;
}
return V4L2_NOERROR ;
}
when executed the VIDIOC_DQBUF IOCTL,the return value was right, but the
value of buf.length would always be zero. Then I used the read()
function to read raw data in the file handle for debug, and I can get
the raw data. Anybody have met this issue before ? Who can give me some
advices or tell me what is wrong , thanks a lot ~
--
=
DongSoo, Nathaniel Kim
Engineer
Mobile S/W Platform Lab.
Digital Media Communications RD Centre
Samsung Electronics CO., LTD.
e-mail : dongsoo@gmail.com
dongsoo45@samsung.com
--
To unsubscribe from this list: send the line unsubscribe linux-media in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: About the VIDIOC_DQBUF
Hi Dongsoo, Nathaniel ~
You must be expert on V4l2 ~ Thanks very much for your help and advice
~!~
I used the MXC camera interface driver from Fressscale ,I readed the
driver interface just now ,and have fouded that the driver not modified
the buf.lenth but buf.byteused . You are very right , I will use the
buf.byteused instead of buf.length ~
There is also a problem I want to consult to you ~ Can i get a full
frame with the below method if the driver have no problem ?
memcpy((mCameraProwave-getPreviewHeap())-base(),
v4l2Buffer[buf.index].start, buf.byteused) ;
Because I just need to implement a hal for getting the frame data and
post it to top layer , so I used the memcpy simply . Am I right ~ ? Or
what about your advice ?
Thanks a lot ~~
在 2009-06-08一的 15:56 +0900，Dongsoo, Nathaniel Kim写道：
Hello Xie,
I'm not sure which camera interface driver you are using, but it seems
to be camera interface driver's problem. Let me guess, are you using
pxa camera interface driver from Marvell?(proprietary but not in up
stream kernel)
It just looks like that camera interface driver is not returning
proper data in dqbuf.
And one more thing. I prefer to use byteused rather than length in
buf. because as far as I know the size of preview data from camera is
in byte unit which we need to copy to memory. But it should be
possible to use length, I guess..
Cheers,
Nate
On Mon, Jun 8, 2009 at 11:05 AM, xieyili@gmail.com wrote:
Dear all ~~
I have met a issue when I used the mmap method for previewing . I just
used the standard code as spec to get the image data :
status_t CameraHardwareProwave::V4l2Camera::v4l2CaptureMainloop()
{
LOG_FUNCTION_NAME
int rt ;
unsigned int i ;
fd_set fds ;
struct timeval tv ;
struct v4l2_buffer buf ;
for(;;){
FD_ZERO(fds) ;
FD_SET(v4l2Fd, fds) ;
//now the time is long ,just for debug
tv.tv_sec = 2 ;
tv.tv_usec = 0 ;
rt = select(v4l2Fd + 1, fds, NULL, NULL, tv) ;
LOGD(The value of select return : %d\n, rt) ;
/** for debug
if(V4L2_NOERROR != v4l2ReadFrame()){
LOGE(READ ERROR) ;
}
***/
if(-1 == rt){
LOGE(there is something wrong in select
function(select)) ;
//no defined error manage
return V4L2_IOCTL_ERROR ;
}
if(0 == rt){
LOGE(wait for data timeout in select) ;
return V4L2_TIMEOUT ;
}
memset(buf, 0, sizeof(buf)) ;
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE ;
buf.memory = V4L2_MEMORY_MMAP ;
if(-1 == ioctl(v4l2Fd, VIDIOC_DQBUF, buf)){
LOGE(there is something wrong in dequeue
buffer(VIDIOC_DQBUF)) ;
return V4L2_IOCTL_ERROR ;
}
assert(i n_buf) ;
LOGE(buf.index 0buf.length = %d %d \n, buf.index ,
buf.length) ;
memcpy((mCameraProwave-getPreviewHeap())-base(),
v4l2Buffer[buf.index].start, buf.length) ;
if(-1 == ioctl(v4l2Fd, VIDIOC_QBUF, buf)){
LOGE(there is something wrong in enqueue
buffer(VIDIOC_QBUF)) ;
return V4L2_IOCTL_ERROR ;
}
//break ; //i don't know whether the break is needed ;
}
return V4L2_NOERROR ;
}
when executed the VIDIOC_DQBUF IOCTL,the return value was right, but the
value of buf.length would always be zero. Then I used the read()
function to read raw data in the file handle for debug, and I can get
the raw data. Anybody have met this issue before ? Who can give me some
advices or tell me what is wrong , thanks a lot ~
--
To unsubscribe from this list: send the line unsubscribe linux-media in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: About the VIDIOC_DQBUF
Hi,
Sorry I'm not an expert, you can expect expertise from maintainers not from me.
But before answering your question about capturing, I'm not sure about
what the full frame means. I just assume that you meant to say the
biggest resolution of image frame, right?
So, when you are to capture a full resolution data while preview is
working, you need to stop preview with streamoff, re-configure
resolution with s_fmt to external camera module and start capturing
issuing streamon with re-configured resolution. I think you are
well-aware with this, aren't you? And in my opinion, memcpy may be
cool for that. What else are you expecting to use? and for what?
Anyway, I wish you luck.
Cheers,
Nate
On Mon, Jun 8, 2009 at 5:02 PM, xieyili@gmail.com wrote:
Hi Dongsoo, Nathaniel ~
You must be expert on V4l2 ~ Thanks very much for your help and advice
~!~
I used the MXC camera interface driver from Fressscale ,I readed the
driver interface just now ,and have fouded that the driver not modified
the buf.lenth but buf.byteused . You are very right , I will use the
buf.byteused instead of buf.length ~
There is also a problem I want to consult to you ~ Can i get a full
frame with the below method if the driver have no problem ?
memcpy((mCameraProwave-getPreviewHeap())-base(),
v4l2Buffer[buf.index].start, buf.byteused) ;
Because I just need to implement a hal for getting the frame data and
post it to top layer , so I used the memcpy simply . Am I right ~ ? Or
what about your advice ?
Thanks a lot ~~
在 2009-06-08一的 15:56 +0900，Dongsoo, Nathaniel Kim写道：
Hello Xie,
I'm not sure which camera interface driver you are using, but it seems
to be camera interface driver's problem. Let me guess, are you using
pxa camera interface driver from Marvell?(proprietary but not in up
stream kernel)
It just looks like that camera interface driver is not returning
proper data in dqbuf.
And one more thing. I prefer to use byteused rather than length in
buf. because as far as I know the size of preview data from camera is
in byte unit which we need to copy to memory. But it should be
possible to use length, I guess..
Cheers,
Nate
On Mon, Jun 8, 2009 at 11:05 AM, xieyili@gmail.com wrote:
Dear all ~~
I have met a issue when I used the mmap method for previewing . I just
used the standard code as spec to get the image data :
status_t CameraHardwareProwave::V4l2Camera::v4l2CaptureMainloop()
{
LOG_FUNCTION_NAME
int rt ;
unsigned int i ;
fd_set fds ;
struct timeval tv ;
struct v4l2_buffer buf ;
for(;;){
FD_ZERO(fds) ;
FD_SET(v4l2Fd, fds) ;
//now the time is long ,just for debug
tv.tv_sec = 2 ;
tv.tv_usec = 0 ;
rt = select(v4l2Fd + 1, fds, NULL, NULL, tv) ;
LOGD(The value of select return : %d\n, rt) ;
/** for debug
if(V4L2_NOERROR != v4l2ReadFrame()){
LOGE(READ ERROR) ;
}
***/
if(-1 == rt){
LOGE(there is something wrong in select
function(select)) ;
//no defined error manage
return V4L2_IOCTL_ERROR ;
}
if(0 == rt){
LOGE(wait for data timeout in select) ;
return V4L2_TIMEOUT ;
}
memset(buf, 0, sizeof(buf)) ;
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE ;
buf.memory = V4L2_MEMORY_MMAP ;
if(-1 == ioctl(v4l2Fd, VIDIOC_DQBUF, buf)){
LOGE(there is something wrong in dequeue
buffer(VIDIOC_DQBUF)) ;
return V4L2_IOCTL_ERROR ;
}
assert(i n_buf) ;
LOGE(buf.index 0buf.length = %d %d \n, buf.index ,
buf.length) ;
memcpy((mCameraProwave-getPreviewHeap())-base(),
v4l2Buffer[buf.index].start, buf.length) ;
if(-1 == ioctl(v4l2Fd, VIDIOC_QBUF, buf)){
LOGE(there is something wrong in enqueue
buffer(VIDIOC_QBUF)) ;
return V4L2_IOCTL_ERROR ;
}
//break ; //i don't know whether the break is needed ;
}
return V4L2_NOERROR ;
}
when executed the VIDIOC_DQBUF IOCTL,the return value was right, but the
value of buf.length would always be zero. Then I used the read()
function to read raw data in the file handle for debug, and I can get
the raw data. Anybody have met this issue before ? Who can give me some
advices or tell me what is wrong , thanks a lot ~
--
=
DongSoo, Nathaniel Kim
Engineer
Mobile S/W Platform Lab.
Digital Media Communications RD Centre
Samsung Electronics CO., LTD.
e-mail :
Re: About the VIDIOC_DQBUF
hi ~~ Dongsoo, Nathaniel ~
I am sorry for disturbing you, and not descripe the question clear ~
Thanks very much for your help ~~
I know that I must stop preview with streamoff and re-configure with
s_fmt ~~ I have asked to you before ~!~
The full frame means a complete frame ~Because I just need to get the
frame data and post it to multimedia framework, so I want to consult to
you that if I can get a complete frame with memcpy ~~
I want to know that can I get a complete frame from buf.start to the
end , and the memory-lenth is buf.byteused ~
buf.byteused
|-|
buf.startend
在 2009-06-08一的 20:40 +0900，Dongsoo, Nathaniel Kim写道：
Hi,
Sorry I'm not an expert, you can expect expertise from maintainers not from
me.
But before answering your question about capturing, I'm not sure about
what the full frame means. I just assume that you meant to say the
biggest resolution of image frame, right?
So, when you are to capture a full resolution data while preview is
working, you need to stop preview with streamoff, re-configure
resolution with s_fmt to external camera module and start capturing
issuing streamon with re-configured resolution. I think you are
well-aware with this, aren't you? And in my opinion, memcpy may be
cool for that. What else are you expecting to use? and for what?
Anyway, I wish you luck.
Cheers,
Nate
On Mon, Jun 8, 2009 at 5:02 PM, xieyili@gmail.com wrote:
Hi Dongsoo, Nathaniel ~
You must be expert on V4l2 ~ Thanks very much for your help and advice
~!~
I used the MXC camera interface driver from Fressscale ,I readed the
driver interface just now ,and have fouded that the driver not modified
the buf.lenth but buf.byteused . You are very right , I will use the
buf.byteused instead of buf.length ~
There is also a problem I want to consult to you ~ Can i get a full
frame with the below method if the driver have no problem ?
memcpy((mCameraProwave-getPreviewHeap())-base(),
v4l2Buffer[buf.index].start, buf.byteused) ;
Because I just need to implement a hal for getting the frame data and
post it to top layer , so I used the memcpy simply . Am I right ~ ? Or
what about your advice ?
Thanks a lot ~~
在 2009-06-08一的 15:56 +0900，Dongsoo, Nathaniel Kim写道：
Hello Xie,
I'm not sure which camera interface driver you are using, but it seems
to be camera interface driver's problem. Let me guess, are you using
pxa camera interface driver from Marvell?(proprietary but not in up
stream kernel)
It just looks like that camera interface driver is not returning
proper data in dqbuf.
And one more thing. I prefer to use byteused rather than length in
buf. because as far as I know the size of preview data from camera is
in byte unit which we need to copy to memory. But it should be
possible to use length, I guess..
Cheers,
Nate
On Mon, Jun 8, 2009 at 11:05 AM, xieyili@gmail.com wrote:
Dear all ~~
I have met a issue when I used the mmap method for previewing . I just
used the standard code as spec to get the image data :
status_t CameraHardwareProwave::V4l2Camera::v4l2CaptureMainloop()
{
LOG_FUNCTION_NAME
int rt ;
unsigned int i ;
fd_set fds ;
struct timeval tv ;
struct v4l2_buffer buf ;
for(;;){
FD_ZERO(fds) ;
FD_SET(v4l2Fd, fds) ;
//now the time is long ,just for debug
tv.tv_sec = 2 ;
tv.tv_usec = 0 ;
rt = select(v4l2Fd + 1, fds, NULL, NULL, tv) ;
LOGD(The value of select return : %d\n, rt) ;
/** for debug
if(V4L2_NOERROR != v4l2ReadFrame()){
LOGE(READ ERROR) ;
}
***/
if(-1 == rt){
LOGE(there is something wrong in select
function(select)) ;
//no defined error manage
return V4L2_IOCTL_ERROR ;
}
if(0 == rt){
LOGE(wait for data timeout in select) ;
return V4L2_TIMEOUT ;
}
memset(buf, 0, sizeof(buf)) ;
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE ;
buf.memory = V4L2_MEMORY_MMAP ;
if(-1 == ioctl(v4l2Fd, VIDIOC_DQBUF, buf)){
LOGE(there is something wrong in dequeue
buffer(VIDIOC_DQBUF)) ;
return V4L2_IOCTL_ERROR ;
}
assert(i n_buf) ;
LOGE(buf.index 0buf.length = %d %d \n, buf.index ,
buf.length) ;
memcpy((mCameraProwave-getPreviewHeap())-base(),
v4l2Buffer[buf.index].start, buf.length) ;
About the VIDIOC_DQBUF
Dear all ~~
I have met a issue when I used the mmap method for previewing . I just
used the standard code as spec to get the image data :
status_t CameraHardwareProwave::V4l2Camera::v4l2CaptureMainloop()
{
LOG_FUNCTION_NAME
int rt ;
unsigned int i ;
fd_set fds ;
struct timeval tv ;
struct v4l2_buffer buf ;
for(;;){
FD_ZERO(fds) ;
FD_SET(v4l2Fd, fds) ;
//now the time is long ,just for debug
tv.tv_sec = 2 ;
tv.tv_usec = 0 ;
rt = select(v4l2Fd + 1, fds, NULL, NULL, tv) ;
LOGD(The value of select return : %d\n, rt) ;
/** for debug
if(V4L2_NOERROR != v4l2ReadFrame()){
LOGE(READ ERROR) ;
}
***/
if(-1 == rt){
LOGE(there is something wrong in select
function(select)) ;
//no defined error manage
return V4L2_IOCTL_ERROR ;
}
if(0 == rt){
LOGE(wait for data timeout in select) ;
return V4L2_TIMEOUT ;
}
memset(buf, 0, sizeof(buf)) ;
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE ;
buf.memory = V4L2_MEMORY_MMAP ;
if(-1 == ioctl(v4l2Fd, VIDIOC_DQBUF, buf)){
LOGE(there is something wrong in dequeue
buffer(VIDIOC_DQBUF)) ;
return V4L2_IOCTL_ERROR ;
}
assert(i n_buf) ;
LOGE(buf.index 0buf.length = %d %d \n, buf.index ,
buf.length) ;
memcpy((mCameraProwave-getPreviewHeap())-base(),
v4l2Buffer[buf.index].start, buf.length) ;
if(-1 == ioctl(v4l2Fd, VIDIOC_QBUF, buf)){
LOGE(there is something wrong in enqueue
buffer(VIDIOC_QBUF)) ;
return V4L2_IOCTL_ERROR ;
}
//break ; //i don't know whether the break is needed ;
}
return V4L2_NOERROR ;
}
when executed the VIDIOC_DQBUF IOCTL,the return value was right, but the
value of buf.length would always be zero. Then I used the read()
function to read raw data in the file handle for debug, and I can get
the raw data. Anybody have met this issue before ? Who can give me some
advices or tell me what is wrong , thanks a lot ~
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