go7007 development

go7007 development

[Pete]

Hello,

I am working on adding the Sensoray 2250 to the go7007 staging tree,
starting from GregKH's staging patch here:
http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/
gregkh-05-staging-2.6.27.patch   

In particular, we are stuck how to change the MPEG format with standard 
IOCTL calls.  In particular, this comment in the driver go7007.h below 
needs explanation:

/* DEPRECATED -- use V4L2_PIX_FMT_MPEG and then call GO7007IOC_S_MPEG_PARAMS
 * to select between MPEG1, MPEG2, and MPEG4 */
#define V4L2_PIX_FMT_MPEG4     v4l2_fourcc('M','P','G','4') /* MPEG4         */

The existing driver, for backward-compatibility , allowed
V4L2_PIX_FMT_MPEG4 to be used for v4l2_format.pixelformat with
VIDIOC_S_FMT.

GO7007IOC_S_MPEG_PARAMS is a custom ioctl call and we would rather have
this done through v4l2 calls. We also can't seem to find where MPEG1,
MPEG2, and MPEG4 elementary streams are defined in the V4L2 API.  We
checked other drivers, but could not find anything.  The closest thing
we found was the V4L2_CID_MPEG_STREAM_TYPE control, but the enums do not
define elementary streams nor MPEG4.

Your advice is appreciated.

Thanks.
-- 
Pete Eberlein
Sensoray Co., Inc.
Email: pete@sensoray.com
http://www.sensoray.com

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Re: go7007 development

[Hans Verkuil]

Hi Pete,

On Friday 17 October 2008 17:21:51 Pete wrote:
> Hello,
>
> I am working on adding the Sensoray 2250 to the go7007 staging tree,
> starting from GregKH's staging patch here:
> http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/
> gregkh-05-staging-2.6.27.patch
>
> In particular, we are stuck how to change the MPEG format with
> standard IOCTL calls.  In particular, this comment in the driver
> go7007.h below needs explanation:
>
> /* DEPRECATED -- use V4L2_PIX_FMT_MPEG and then call
> GO7007IOC_S_MPEG_PARAMS * to select between MPEG1, MPEG2, and MPEG4
> */
> #define V4L2_PIX_FMT_MPEG4     v4l2_fourcc('M','P','G','4') /* MPEG4 
>        */
>
> The existing driver, for backward-compatibility , allowed
> V4L2_PIX_FMT_MPEG4 to be used for v4l2_format.pixelformat with
> VIDIOC_S_FMT.
>
> GO7007IOC_S_MPEG_PARAMS is a custom ioctl call and we would rather
> have this done through v4l2 calls. We also can't seem to find where
> MPEG1, MPEG2, and MPEG4 elementary streams are defined in the V4L2
> API.  We checked other drivers, but could not find anything.  The
> closest thing we found was the V4L2_CID_MPEG_STREAM_TYPE control, but
> the enums do not define elementary streams nor MPEG4.
>
> Your advice is appreciated.
>
> Thanks.

It would be really nice to have this driver in the kernel.

All MPEG streams use V4L2_PIX_FMT_MPEG and set the exact stream type 
through V4L2_CID_MPEG_STREAM_TYPE. You probably need to add a few new 
stream types to this control for the elementary streams. I think 
something like TYPE_MPEG_ELEM might do the trick, and then you can use 
the audio and video encoding controls to select the precise audio/video 
encoding.

I don't know enough about the capabilities, so perhaps 
TYPE_MPEG1/2/4_ELEM is required instead of a more generic 
TYPE_MPEG_ELEM.

Since I designed the MPEG API for V4L2 I guess I'm the right person to 
help you. I also have a Plextor TV402U since I always wanted to get the 
go7007 driver into the kernel, but I never had the time so I'm glad 
you've picked it up.

Regards,

	Hans

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Re: go7007 development

[Dean Anderson]

Hans Verkuil wrote:
> Hi Pete,
>
> On Friday 17 October 2008 17:21:51 Pete wrote:
>   
>> Hello,
>>
>> I am working on adding the Sensoray 2250 to the go7007 staging tree,
>> starting from GregKH's staging patch here:
>> http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/
>> gregkh-05-staging-2.6.27.patch
>>
>> In particular, we are stuck how to change the MPEG format with
>> standard IOCTL calls.  In particular, this comment in the driver
>> go7007.h below needs explanation:
>>
>> /* DEPRECATED -- use V4L2_PIX_FMT_MPEG and then call
>> GO7007IOC_S_MPEG_PARAMS * to select between MPEG1, MPEG2, and MPEG4
>> */
>> #define V4L2_PIX_FMT_MPEG4     v4l2_fourcc('M','P','G','4') /* MPEG4 
>>        */
>>
>> The existing driver, for backward-compatibility , allowed
>> V4L2_PIX_FMT_MPEG4 to be used for v4l2_format.pixelformat with
>> VIDIOC_S_FMT.
>>
>> GO7007IOC_S_MPEG_PARAMS is a custom ioctl call and we would rather
>> have this done through v4l2 calls. We also can't seem to find where
>> MPEG1, MPEG2, and MPEG4 elementary streams are defined in the V4L2
>> API.  We checked other drivers, but could not find anything.  The
>> closest thing we found was the V4L2_CID_MPEG_STREAM_TYPE control, but
>> the enums do not define elementary streams nor MPEG4.
>>
>> Your advice is appreciated.
>>
>> Thanks.
>>     
>
> It would be really nice to have this driver in the kernel.
>
> All MPEG streams use V4L2_PIX_FMT_MPEG and set the exact stream type 
> through V4L2_CID_MPEG_STREAM_TYPE. You probably need to add a few new 
> stream types to this control for the elementary streams. I think 
> something like TYPE_MPEG_ELEM might do the trick, and then you can use 
> the audio and video encoding controls to select the precise audio/video 
> encoding.
>
> I don't know enough about the capabilities, so perhaps 
> TYPE_MPEG1/2/4_ELEM is required instead of a more generic 
> TYPE_MPEG_ELEM.
>
>   
The generic approach seems better.  There will be boards with H264 
encapsulated in MPEG2 transport stream.  I'd recommend keeping the 
encapsulation/mux format in V4L2_CID_MPEG_STREAM_TYPE, but not 
necessarily the encoding. 

Otherwise you'll have V4L2_MPEG_STREAM_TYPE_MPEG2_TS_MPEG4_ENCODING, 
etc..  Maybe V4L2_CID_MPEG_STREAM_TYPE needs a comment that it is the 
encapsulation(or mux format), and the encoding should be defined in 
V4L2_CID_MPEG_VIDEO_ENCODING?

So for this Go7007, we suggest adding V4L2_MPEG_STREAM_TYPE_ELEM to 
V4L2_CID_MPEG_STREAM_TYPE.
We also suggest adding V4L2_MPEG_VIDEO_ENCODING_MPEG_4 to 
V4L2_CID_MPEG_VIDEO_ENCODING.  Of course, there is the question of what 
version of MPEG4, but we'll leave that for another day.

What do you think?

> Since I designed the MPEG API for V4L2 I guess I'm the right person to 
> help you. I also have a Plextor TV402U since I always wanted to get the 
> go7007 driver into the kernel, but I never had the time so I'm glad 
> you've picked it up.
>
> Regards,
>
> 	Hans
>
>   
Good to hear, and thanks for the quick response.

Dean

-- 
Dean Anderson
Sensoray Co., Inc.
Email: dean@sensoray.com
http://www.sensoray.com



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Re: go7007 development

[Hans Verkuil]

On Friday 17 October 2008 18:07:41 Dean Anderson wrote:
> Hans Verkuil wrote:
> > Hi Pete,
> >
> > On Friday 17 October 2008 17:21:51 Pete wrote:
> >> Hello,
> >>
> >> I am working on adding the Sensoray 2250 to the go7007 staging
> >> tree, starting from GregKH's staging patch here:
> >> http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/
> >> gregkh-05-staging-2.6.27.patch
> >>
> >> In particular, we are stuck how to change the MPEG format with
> >> standard IOCTL calls.  In particular, this comment in the driver
> >> go7007.h below needs explanation:
> >>
> >> /* DEPRECATED -- use V4L2_PIX_FMT_MPEG and then call
> >> GO7007IOC_S_MPEG_PARAMS * to select between MPEG1, MPEG2, and
> >> MPEG4 */
> >> #define V4L2_PIX_FMT_MPEG4     v4l2_fourcc('M','P','G','4') /*
> >> MPEG4 */
> >>
> >> The existing driver, for backward-compatibility , allowed
> >> V4L2_PIX_FMT_MPEG4 to be used for v4l2_format.pixelformat with
> >> VIDIOC_S_FMT.
> >>
> >> GO7007IOC_S_MPEG_PARAMS is a custom ioctl call and we would rather
> >> have this done through v4l2 calls. We also can't seem to find
> >> where MPEG1, MPEG2, and MPEG4 elementary streams are defined in
> >> the V4L2 API.  We checked other drivers, but could not find
> >> anything.  The closest thing we found was the
> >> V4L2_CID_MPEG_STREAM_TYPE control, but the enums do not define
> >> elementary streams nor MPEG4.
> >>
> >> Your advice is appreciated.
> >>
> >> Thanks.
> >
> > It would be really nice to have this driver in the kernel.
> >
> > All MPEG streams use V4L2_PIX_FMT_MPEG and set the exact stream
> > type through V4L2_CID_MPEG_STREAM_TYPE. You probably need to add a
> > few new stream types to this control for the elementary streams. I
> > think something like TYPE_MPEG_ELEM might do the trick, and then
> > you can use the audio and video encoding controls to select the
> > precise audio/video encoding.
> >
> > I don't know enough about the capabilities, so perhaps
> > TYPE_MPEG1/2/4_ELEM is required instead of a more generic
> > TYPE_MPEG_ELEM.
>
> The generic approach seems better.  There will be boards with H264
> encapsulated in MPEG2 transport stream.  I'd recommend keeping the
> encapsulation/mux format in V4L2_CID_MPEG_STREAM_TYPE, but not
> necessarily the encoding.
>
> Otherwise you'll have V4L2_MPEG_STREAM_TYPE_MPEG2_TS_MPEG4_ENCODING,
> etc..  Maybe V4L2_CID_MPEG_STREAM_TYPE needs a comment that it is the
> encapsulation(or mux format), and the encoding should be defined in
> V4L2_CID_MPEG_VIDEO_ENCODING?

I think the v4l2 spec is clear enough on this topic.

> So for this Go7007, we suggest adding V4L2_MPEG_STREAM_TYPE_ELEM to
> V4L2_CID_MPEG_STREAM_TYPE.
> We also suggest adding V4L2_MPEG_VIDEO_ENCODING_MPEG_4 to
> V4L2_CID_MPEG_VIDEO_ENCODING.  Of course, there is the question of
> what version of MPEG4, but we'll leave that for another day.
>
> What do you think?

Agreed. Note that V4L2_MPEG_VIDEO_ENCODING_MPEG_4_AVC already exists in 
the master v4l-dvb tree http://linuxtv.org/hg/v4l-dvb, also some newer 
audio encodings. These are merged in the latest 2.6.28 git tree as 
well.

When the go7007 driver has stabilized a bit and switched to the generic 
ioctls rather than using custom ioctls then you probably want to have 
you code merged in v4l-dvb. I expect a lot of internal API additions 
and improvements in the coming months so it's probably good to pay 
attention to the master tree to see what is happening there.

>
> > Since I designed the MPEG API for V4L2 I guess I'm the right person
> > to help you. I also have a Plextor TV402U since I always wanted to
> > get the go7007 driver into the kernel, but I never had the time so
> > I'm glad you've picked it up.
> >
> > Regards,
> >
> > 	Hans
>
> Good to hear, and thanks for the quick response.

No problem.

Regards,

	Hans

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[PATCH] Add MPEG4 and Elementary streams (was Re: go7007 development)

[Pete Eberlein]

Hello Hans,

On Fri, 2008-10-17 at 17:36 +0200, Hans Verkuil wrote:
> All MPEG streams use V4L2_PIX_FMT_MPEG and set the exact stream type 
> through V4L2_CID_MPEG_STREAM_TYPE. You probably need to add a few new 
> stream types to this control for the elementary streams. I think 
> something like TYPE_MPEG_ELEM might do the trick, and then you can use 
> the audio and video encoding controls to select the precise audio/video 
> encoding.

Here is a patch that adds the two defines we need for the go7007 driver
extended MPEG controls.  Please consider it for inclusion in the v4l-dvb
tree.

V4L2_MPEG_STREAM_TYPE_MPEG_ELEM will be used for elementary MPEG
streams, whose type and encoding will be determined by examining a
header in the stream.  For more information, see
http://en.wikipedia.org/wiki/Elementary_stream

V4L2_MPEG_VIDEO_ENCODING_MPEG_4 will be used for MPEG-4 Part 2 (Simple
Profile, Advanced Simple Profile, etc) encoding.  This is not the same
as MPEG-4 AVC (Part 10, Advanced Video Coding).

Thanks.
-- 
Pete Eberlein
Sensoray Co., Inc.
Email: pete@sensoray.com
http://www.sensoray.com


Signed-off-by: Pete Eberlein <pete@sensoray.com>
---

diff -r fe810917c6ca linux/include/linux/videodev2.h
--- a/linux/include/linux/videodev2.h	Fri Oct 24 13:19:14 2008 -0200
+++ b/linux/include/linux/videodev2.h	Fri Oct 24 09:57:46 2008 -0700
@@ -892,6 +892,7 @@ enum v4l2_mpeg_stream_type {
 	V4L2_MPEG_STREAM_TYPE_MPEG2_DVD  = 3, /* MPEG-2 DVD-compatible stream */
 	V4L2_MPEG_STREAM_TYPE_MPEG1_VCD  = 4, /* MPEG-1 VCD-compatible stream */
 	V4L2_MPEG_STREAM_TYPE_MPEG2_SVCD = 5, /* MPEG-2 SVCD-compatible stream */
+	V4L2_MPEG_STREAM_TYPE_MPEG_ELEM  = 6, /* MPEG elementary stream */
 };
 #define V4L2_CID_MPEG_STREAM_PID_PMT 		(V4L2_CID_MPEG_BASE+1)
 #define V4L2_CID_MPEG_STREAM_PID_AUDIO 		(V4L2_CID_MPEG_BASE+2)
@@ -1027,6 +1028,7 @@ enum v4l2_mpeg_video_encoding {
 	V4L2_MPEG_VIDEO_ENCODING_MPEG_1     = 0,
 	V4L2_MPEG_VIDEO_ENCODING_MPEG_2     = 1,
 	V4L2_MPEG_VIDEO_ENCODING_MPEG_4_AVC = 2,
+	V4L2_MPEG_VIDEO_ENCODING_MPEG_4     = 3,
 };
 #define V4L2_CID_MPEG_VIDEO_ASPECT 		(V4L2_CID_MPEG_BASE+201)
 enum v4l2_mpeg_video_aspect {

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