Re: [PATCH 0/4] Enable Hantro G1 post-processor
Hello,
On 9/12/19 8:35 AM, Ezequiel Garcia wrote:
> On Thu, 2019-09-12 at 14:52 +0900, Tomasz Figa wrote:
>> On Thu, Sep 12, 2019 at 4:49 AM Nicolas Dufresne
>> wrote:
>>> Le mercredi 11 septembre 2019 à 09:27 +0100, Ezequiel Garcia a écrit :
On Mon, 2019-09-09 at 16:07 +0900, Tomasz Figa wrote:
> Hi Ezequiel,
>
> On Wed, Sep 4, 2019 at 3:17 AM Ezequiel Garcia
> wrote:
>> Hi all,
>>
>> This series enables the post-processor support available
>> on the Hantro G1 VPU. The post-processor block can be
>> pipelined with the decoder hardware, allowing to perform
>> operations such as color conversion, scaling, rotation,
>> cropping, among others.
>>
>> The decoder hardware needs its own set of NV12 buffers
>> (the native decoder format), and the post-processor is the
>> owner of the CAPTURE buffers. This allows the application
>> get processed (scaled, converted, etc) buffers, completely
>> transparently.
>>
>> This feature is implemented by exposing other CAPTURE pixel
>> formats to the application (ENUM_FMT). When the application
>> sets a pixel format other than NV12, the driver will enable
>> and use the post-processor transparently.
>
> I'll try to review the series a bit later, but a general comment here
> is that the userspace wouldn't have a way to distinguish between the
> native and post-processed formats. I'm pretty much sure that
> post-processing at least imposes some power penalty, so it would be
> good if the userspace could avoid it if unnecessary.
>
Hm, that's true, good catch.
So, it would be desirable to retain the current behavior of allowing
the application to just set a different pixel format and get
a post-processed frame, transparently.
But at the same time, it would be nice if the application is somehow
aware of the post-processing happening. Maybe we can expose a more
accurate media controller topology, have applications enable
the post-processing pipeline explicitly.
>>>
>>> How it works on the stateful side is that userspace set the encoding
>>> type (the codec), then passes a header (in our case, there will be
>>> parsed structures replacing this) first. The driver then configure
>>> capture format, giving a hint of the "default" or "native" format. This
>>> may or may not be sufficient, but it does work in giving userspace a
>>> hint.
>>
>> The bad side of that is that we can't handle more than 1 native format.
>>
>> For the most backwards-compatible behavior, sorting the results of
>> ENUM_FMT according to format preference would allow the applications
>> that choose the first format returned that works for them to choose
>> the best one.
>>
>> For a further improvement, an ENUM_FMT flag that tells the userspace
>> that a format is preferred could work.
>>
>> That said, modelling the pipeline appropriately using the media
>> controller is the idea I like the most, because it's the most
>> comprehensive solution. That would have to be well specified and
>> documented, though, and sounds like a long term effort.
>>
I was playing with vimc to emulate this topology.
What I would suggest is a topology like this:
Device topology
- entity 1: Decoder (2 pads, 3 links)
type V4L2 subdev subtype Unknown flags 0
pad0: Sink
<- "M2M Video Node":1 [ENABLED]
pad1: Source
-> "M2M Video Node":0 [ENABLED]
-> "PostProc":0 []
- entity 4: PostProc (2 pads, 2 links)
type V4L2 subdev subtype Unknown flags 0
pad0: Sink
<- "Decoder":1 []
pad1: Source
-> "M2M Video Node":0 []
- entity 7: M2M Video Node (2 pads, 3 links)
type Node subtype V4L flags 0
device node name /dev/video0
pad0: Sink
<- "Decoder":1 [ENABLED]
<- "PostProc":1 []
pad1: Source
-> "Decoder":0 [ENABLED]
Dot file:
-
digraph board {
rankdir=TB
n0001 [label="{{ 0} | Decoder\n | { 1}}",
shape=Mrecord, style=filled, fillcolor=green]
n0001:port1 -> n0007
n0001:port1 -> n0004:port0 [style=dashed]
n0004 [label="{{ 0} | PostProc\n | { 1}}",
shape=Mrecord, style=filled, fillcolor=green]
n0004:port1 -> n0007 [style=dashed]
n0007 [label="M2M Video Node\n/dev/video0", shape=box,
style=filled, fillcolor=yellow]
n0007 -> n0001:port0
}
Also, as you mentioned in patch 4:
> On the YUV-to-RGB path, the post-processing pipeline
> allows to modify the image contrast, brigthness and saturation,
> so additional user controls are added to expose them.
So I think it would make sense to expose these controls in the post-processor
subdev,
through a /dev/v4l-subdev0, this avoids having a dynamic set of controls in the
video node
depending on th
Re: [PATCH 0/4] Enable Hantro G1 post-processor
On Thu, 2019-09-12 at 14:52 +0900, Tomasz Figa wrote: > On Thu, Sep 12, 2019 at 4:49 AM Nicolas Dufresne wrote: > > Le mercredi 11 septembre 2019 à 09:27 +0100, Ezequiel Garcia a écrit : > > > On Mon, 2019-09-09 at 16:07 +0900, Tomasz Figa wrote: > > > > Hi Ezequiel, > > > > > > > > On Wed, Sep 4, 2019 at 3:17 AM Ezequiel Garcia > > > > wrote: > > > > > Hi all, > > > > > > > > > > This series enables the post-processor support available > > > > > on the Hantro G1 VPU. The post-processor block can be > > > > > pipelined with the decoder hardware, allowing to perform > > > > > operations such as color conversion, scaling, rotation, > > > > > cropping, among others. > > > > > > > > > > The decoder hardware needs its own set of NV12 buffers > > > > > (the native decoder format), and the post-processor is the > > > > > owner of the CAPTURE buffers. This allows the application > > > > > get processed (scaled, converted, etc) buffers, completely > > > > > transparently. > > > > > > > > > > This feature is implemented by exposing other CAPTURE pixel > > > > > formats to the application (ENUM_FMT). When the application > > > > > sets a pixel format other than NV12, the driver will enable > > > > > and use the post-processor transparently. > > > > > > > > I'll try to review the series a bit later, but a general comment here > > > > is that the userspace wouldn't have a way to distinguish between the > > > > native and post-processed formats. I'm pretty much sure that > > > > post-processing at least imposes some power penalty, so it would be > > > > good if the userspace could avoid it if unnecessary. > > > > > > > > > > Hm, that's true, good catch. > > > > > > So, it would be desirable to retain the current behavior of allowing > > > the application to just set a different pixel format and get > > > a post-processed frame, transparently. > > > > > > But at the same time, it would be nice if the application is somehow > > > aware of the post-processing happening. Maybe we can expose a more > > > accurate media controller topology, have applications enable > > > the post-processing pipeline explicitly. > > > > How it works on the stateful side is that userspace set the encoding > > type (the codec), then passes a header (in our case, there will be > > parsed structures replacing this) first. The driver then configure > > capture format, giving a hint of the "default" or "native" format. This > > may or may not be sufficient, but it does work in giving userspace a > > hint. > > The bad side of that is that we can't handle more than 1 native format. > > For the most backwards-compatible behavior, sorting the results of > ENUM_FMT according to format preference would allow the applications > that choose the first format returned that works for them to choose > the best one. > > For a further improvement, an ENUM_FMT flag that tells the userspace > that a format is preferred could work. > > That said, modelling the pipeline appropriately using the media > controller is the idea I like the most, because it's the most > comprehensive solution. That would have to be well specified and > documented, though, and sounds like a long term effort. > Completely agreed. Thanks, Ezequiel
Re: [PATCH 0/4] Enable Hantro G1 post-processor
On Thu, Sep 12, 2019 at 4:49 AM Nicolas Dufresne wrote: > > Le mercredi 11 septembre 2019 à 09:27 +0100, Ezequiel Garcia a écrit : > > On Mon, 2019-09-09 at 16:07 +0900, Tomasz Figa wrote: > > > Hi Ezequiel, > > > > > > On Wed, Sep 4, 2019 at 3:17 AM Ezequiel Garcia > > > wrote: > > > > Hi all, > > > > > > > > This series enables the post-processor support available > > > > on the Hantro G1 VPU. The post-processor block can be > > > > pipelined with the decoder hardware, allowing to perform > > > > operations such as color conversion, scaling, rotation, > > > > cropping, among others. > > > > > > > > The decoder hardware needs its own set of NV12 buffers > > > > (the native decoder format), and the post-processor is the > > > > owner of the CAPTURE buffers. This allows the application > > > > get processed (scaled, converted, etc) buffers, completely > > > > transparently. > > > > > > > > This feature is implemented by exposing other CAPTURE pixel > > > > formats to the application (ENUM_FMT). When the application > > > > sets a pixel format other than NV12, the driver will enable > > > > and use the post-processor transparently. > > > > > > I'll try to review the series a bit later, but a general comment here > > > is that the userspace wouldn't have a way to distinguish between the > > > native and post-processed formats. I'm pretty much sure that > > > post-processing at least imposes some power penalty, so it would be > > > good if the userspace could avoid it if unnecessary. > > > > > > > Hm, that's true, good catch. > > > > So, it would be desirable to retain the current behavior of allowing > > the application to just set a different pixel format and get > > a post-processed frame, transparently. > > > > But at the same time, it would be nice if the application is somehow > > aware of the post-processing happening. Maybe we can expose a more > > accurate media controller topology, have applications enable > > the post-processing pipeline explicitly. > > How it works on the stateful side is that userspace set the encoding > type (the codec), then passes a header (in our case, there will be > parsed structures replacing this) first. The driver then configure > capture format, giving a hint of the "default" or "native" format. This > may or may not be sufficient, but it does work in giving userspace a > hint. The bad side of that is that we can't handle more than 1 native format. For the most backwards-compatible behavior, sorting the results of ENUM_FMT according to format preference would allow the applications that choose the first format returned that works for them to choose the best one. For a further improvement, an ENUM_FMT flag that tells the userspace that a format is preferred could work. That said, modelling the pipeline appropriately using the media controller is the idea I like the most, because it's the most comprehensive solution. That would have to be well specified and documented, though, and sounds like a long term effort. Best regards, Tomasz
Re: [PATCH 0/4] Enable Hantro G1 post-processor
Le mercredi 11 septembre 2019 à 09:27 +0100, Ezequiel Garcia a écrit : > On Mon, 2019-09-09 at 16:07 +0900, Tomasz Figa wrote: > > Hi Ezequiel, > > > > On Wed, Sep 4, 2019 at 3:17 AM Ezequiel Garcia > > wrote: > > > Hi all, > > > > > > This series enables the post-processor support available > > > on the Hantro G1 VPU. The post-processor block can be > > > pipelined with the decoder hardware, allowing to perform > > > operations such as color conversion, scaling, rotation, > > > cropping, among others. > > > > > > The decoder hardware needs its own set of NV12 buffers > > > (the native decoder format), and the post-processor is the > > > owner of the CAPTURE buffers. This allows the application > > > get processed (scaled, converted, etc) buffers, completely > > > transparently. > > > > > > This feature is implemented by exposing other CAPTURE pixel > > > formats to the application (ENUM_FMT). When the application > > > sets a pixel format other than NV12, the driver will enable > > > and use the post-processor transparently. > > > > I'll try to review the series a bit later, but a general comment here > > is that the userspace wouldn't have a way to distinguish between the > > native and post-processed formats. I'm pretty much sure that > > post-processing at least imposes some power penalty, so it would be > > good if the userspace could avoid it if unnecessary. > > > > Hm, that's true, good catch. > > So, it would be desirable to retain the current behavior of allowing > the application to just set a different pixel format and get > a post-processed frame, transparently. > > But at the same time, it would be nice if the application is somehow > aware of the post-processing happening. Maybe we can expose a more > accurate media controller topology, have applications enable > the post-processing pipeline explicitly. How it works on the stateful side is that userspace set the encoding type (the codec), then passes a header (in our case, there will be parsed structures replacing this) first. The driver then configure capture format, giving a hint of the "default" or "native" format. This may or may not be sufficient, but it does work in giving userspace a hint. > > Thanks for the feedback, > Ezequiel > signature.asc Description: This is a digitally signed message part
Re: [PATCH 0/4] Enable Hantro G1 post-processor
Le mercredi 11 septembre 2019 à 09:27 +0100, Ezequiel Garcia a écrit : > On Mon, 2019-09-09 at 16:07 +0900, Tomasz Figa wrote: > > Hi Ezequiel, > > > > On Wed, Sep 4, 2019 at 3:17 AM Ezequiel Garcia > > wrote: > > > Hi all, > > > > > > This series enables the post-processor support available > > > on the Hantro G1 VPU. The post-processor block can be > > > pipelined with the decoder hardware, allowing to perform > > > operations such as color conversion, scaling, rotation, > > > cropping, among others. > > > > > > The decoder hardware needs its own set of NV12 buffers > > > (the native decoder format), and the post-processor is the > > > owner of the CAPTURE buffers. This allows the application > > > get processed (scaled, converted, etc) buffers, completely > > > transparently. > > > > > > This feature is implemented by exposing other CAPTURE pixel > > > formats to the application (ENUM_FMT). When the application > > > sets a pixel format other than NV12, the driver will enable > > > and use the post-processor transparently. > > > > I'll try to review the series a bit later, but a general comment here > > is that the userspace wouldn't have a way to distinguish between the > > native and post-processed formats. I'm pretty much sure that > > post-processing at least imposes some power penalty, so it would be > > good if the userspace could avoid it if unnecessary. > > > > Hm, that's true, good catch. > > So, it would be desirable to retain the current behavior of allowing > the application to just set a different pixel format and get > a post-processed frame, transparently. > > But at the same time, it would be nice if the application is somehow > aware of the post-processing happening. Maybe we can expose a more > accurate media controller topology, have applications enable > the post-processing pipeline explicitly. How it works on the stateful side is that userspace set the encoding type (the codec), then passes a header (in our case, there will be parsed structures replacing this) first. The driver then configure capture format, giving a hint of the "default" or "native" format. This may or may not be sufficient, but it does work in giving userspace a hint. > > Thanks for the feedback, > Ezequiel > signature.asc Description: This is a digitally signed message part
Re: [PATCH 0/4] Enable Hantro G1 post-processor
On Mon, 2019-09-09 at 16:07 +0900, Tomasz Figa wrote: > Hi Ezequiel, > > On Wed, Sep 4, 2019 at 3:17 AM Ezequiel Garcia wrote: > > Hi all, > > > > This series enables the post-processor support available > > on the Hantro G1 VPU. The post-processor block can be > > pipelined with the decoder hardware, allowing to perform > > operations such as color conversion, scaling, rotation, > > cropping, among others. > > > > The decoder hardware needs its own set of NV12 buffers > > (the native decoder format), and the post-processor is the > > owner of the CAPTURE buffers. This allows the application > > get processed (scaled, converted, etc) buffers, completely > > transparently. > > > > This feature is implemented by exposing other CAPTURE pixel > > formats to the application (ENUM_FMT). When the application > > sets a pixel format other than NV12, the driver will enable > > and use the post-processor transparently. > > I'll try to review the series a bit later, but a general comment here > is that the userspace wouldn't have a way to distinguish between the > native and post-processed formats. I'm pretty much sure that > post-processing at least imposes some power penalty, so it would be > good if the userspace could avoid it if unnecessary. > Hm, that's true, good catch. So, it would be desirable to retain the current behavior of allowing the application to just set a different pixel format and get a post-processed frame, transparently. But at the same time, it would be nice if the application is somehow aware of the post-processing happening. Maybe we can expose a more accurate media controller topology, have applications enable the post-processing pipeline explicitly. Thanks for the feedback, Ezequiel
Re: [PATCH 0/4] Enable Hantro G1 post-processor
Hi Ezequiel, On Wed, Sep 4, 2019 at 3:17 AM Ezequiel Garcia wrote: > > Hi all, > > This series enables the post-processor support available > on the Hantro G1 VPU. The post-processor block can be > pipelined with the decoder hardware, allowing to perform > operations such as color conversion, scaling, rotation, > cropping, among others. > > The decoder hardware needs its own set of NV12 buffers > (the native decoder format), and the post-processor is the > owner of the CAPTURE buffers. This allows the application > get processed (scaled, converted, etc) buffers, completely > transparently. > > This feature is implemented by exposing other CAPTURE pixel > formats to the application (ENUM_FMT). When the application > sets a pixel format other than NV12, the driver will enable > and use the post-processor transparently. I'll try to review the series a bit later, but a general comment here is that the userspace wouldn't have a way to distinguish between the native and post-processed formats. I'm pretty much sure that post-processing at least imposes some power penalty, so it would be good if the userspace could avoid it if unnecessary. Best regards, Tomasz
