[libcamera-devel,v1,1/4] ipa: ipu3: Separate out frame context queue as a distinct class

16138 diff mbox series

There are cases where we need more checks and balance to be carried out
by the frame context queue class. For that, separate it out as a
distinct class on which we can build upon.

For now, a minimialistic implementation is provided with .get(frame)
helper which returns a IPAFrameContext pointer for the required frame.
Going ahead more such helpers can be provided to access/modify the
frame context queue.

Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
---
 src/ipa/ipu3/ipa_context.cpp | 57 ++++++++++++++++++++++++++++++++++--
 src/ipa/ipu3/ipa_context.h   | 11 ++++++-
 src/ipa/ipu3/ipu3.cpp        | 18 ++++++------
 3 files changed, 74 insertions(+), 12 deletions(-)

Hi Umang,

On Fri, Jun 03, 2022 at 03:22:56PM +0200, Umang Jain via libcamera-devel wrote:
> There are cases where we need more checks and balance to be carried out
> by the frame context queue class. For that, separate it out as a
> distinct class on which we can build upon.
>
> For now, a minimialistic implementation is provided with .get(frame)
> helper which returns a IPAFrameContext pointer for the required frame.
> Going ahead more such helpers can be provided to access/modify the
> frame context queue.
>
> Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
> Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
> Reviewed-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
> ---
>  src/ipa/ipu3/ipa_context.cpp | 57 ++++++++++++++++++++++++++++++++++--
>  src/ipa/ipu3/ipa_context.h   | 11 ++++++-
>  src/ipa/ipu3/ipu3.cpp        | 18 ++++++------
>  3 files changed, 74 insertions(+), 12 deletions(-)
>
> diff --git a/src/ipa/ipu3/ipa_context.cpp b/src/ipa/ipu3/ipa_context.cpp
> index 13cdb835..9f95a61c 100644
> --- a/src/ipa/ipu3/ipa_context.cpp
> +++ b/src/ipa/ipu3/ipa_context.cpp
> @@ -7,12 +7,18 @@
>
>  #include "ipa_context.h"
>
> +#include <libcamera/base/log.h>
> +
>  /**
>   * \file ipa_context.h
>   * \brief Context and state information shared between the algorithms
>   */
>
> -namespace libcamera::ipa::ipu3 {
> +namespace libcamera {
> +
> +LOG_DECLARE_CATEGORY(IPAIPU3)
> +
> +namespace ipa::ipu3 {
>
>  /**
>   * \struct IPASessionConfiguration
> @@ -211,4 +217,51 @@ IPAFrameContext::IPAFrameContext(uint32_t id, const ControlList &reqControls)
>   * \brief Analogue gain multiplier
>   */
>
> -} /* namespace libcamera::ipa::ipu3 */
> +/**
> + * \class FCQueue
> + * \brief A FIFO circular queue holding IPAFrameContext(s)
> + *
> + * FCQueue holds all the IPAFrameContext(s) related to frames required
> + * to be processed by the IPA at a given point.
> + */
> +
> +/**
> + * \brief FCQueue constructor
> + */
> +FCQueue::FCQueue()
> +{
> +	clear();
> +}
> +
> +/**
> + * \brief Retrieve the IPAFrameContext for the frame
> + * \param[in] frame Frame number for which the IPAFrameContext needs to
> + * retrieved
> + *
> + * \return Pointer to the IPAFrameContext
> + */
> +IPAFrameContext *FCQueue::get(uint32_t frame)
> +{
> +	IPAFrameContext &frameContext = this->at(frame % kMaxFrameContexts);
> +
> +	if (frame != frameContext.frame) {
> +		LOG(IPAIPU3, Warning)
> +			<< "Got wrong frame context for frame" << frame
> +			<< " or frame context doesn't exist yet";
> +	}
> +
> +	return &frameContext;
> +}
> +
> +/**
> + * \brief Clear the FCQueue by resetting all the entries in the ring-buffer
> + */
> +void FCQueue::clear()
> +{
> +	IPAFrameContext initFrameContext;
> +	this->fill(initFrameContext);
> +}
> +
> +} /* namespace ipa::ipu3 */
> +
> +} /* namespace libcamera */
> diff --git a/src/ipa/ipu3/ipa_context.h b/src/ipa/ipu3/ipa_context.h
> index 42e11141..56d281f6 100644
> --- a/src/ipa/ipu3/ipa_context.h
> +++ b/src/ipa/ipu3/ipa_context.h
> @@ -89,11 +89,20 @@ struct IPAFrameContext {
>  	ControlList frameControls;
>  };
>
> +class FCQueue : public std::array<IPAFrameContext, kMaxFrameContexts>

This will expose the full std::array<> interface.
I wonder if this should not rather inherit std::array<> as private and
selectively expose only certain functions. That's what ControlInfoMap
does, as an example.

Then the next question is if we want to have a circular buffer class
in libcamera and make

class FCQueue : public libcamera::CircualBuffer<IPAFrameContext, kMaxFrameContexts>
{

}

> +{
> +public:
> +	FCQueue();
> +
> +	void clear();
> +	IPAFrameContext *get(uint32_t frame);
> +};
> +
>  struct IPAContext {
>  	IPASessionConfiguration configuration;
>  	IPAActiveState activeState;
>
> -	std::array<IPAFrameContext, kMaxFrameContexts> frameContexts;
> +	FCQueue frameContexts;
>  };
>
>  } /* namespace ipa::ipu3 */
> diff --git a/src/ipa/ipu3/ipu3.cpp b/src/ipa/ipu3/ipu3.cpp
> index 2f6bb672..0843d882 100644
> --- a/src/ipa/ipu3/ipu3.cpp
> +++ b/src/ipa/ipu3/ipu3.cpp
> @@ -456,8 +456,8 @@ int IPAIPU3::configure(const IPAConfigInfo &configInfo,
>
>  	/* Clean IPAActiveState at each reconfiguration. */
>  	context_.activeState = {};
> -	IPAFrameContext initFrameContext;
> -	context_.frameContexts.fill(initFrameContext);
> +	context_.frameContexts.clear();
> +

Unecessary empty line

>
>  	if (!validateSensorControls()) {
>  		LOG(IPAIPU3, Error) << "Sensor control validation failed.";
> @@ -569,20 +569,20 @@ void IPAIPU3::processStatsBuffer(const uint32_t frame,
>  	const ipu3_uapi_stats_3a *stats =
>  		reinterpret_cast<ipu3_uapi_stats_3a *>(mem.data());
>
> -	IPAFrameContext &frameContext = context_.frameContexts[frame % kMaxFrameContexts];
> +	IPAFrameContext *frameContext = context_.frameContexts.get(frame);
>
> -	if (frameContext.frame != frame)
> +	if (frameContext->frame != frame)
>  		LOG(IPAIPU3, Warning) << "Frame " << frame << " does not match its frame context";
>
> -	frameContext.sensor.exposure = sensorControls.get(V4L2_CID_EXPOSURE).get<int32_t>();
> -	frameContext.sensor.gain = camHelper_->gain(sensorControls.get(V4L2_CID_ANALOGUE_GAIN).get<int32_t>());
> +	frameContext->sensor.exposure = sensorControls.get(V4L2_CID_EXPOSURE).get<int32_t>();
> +	frameContext->sensor.gain = camHelper_->gain(sensorControls.get(V4L2_CID_ANALOGUE_GAIN).get<int32_t>());
>
>  	double lineDuration = context_.configuration.sensor.lineDuration.get<std::micro>();
>  	int32_t vBlank = context_.configuration.sensor.defVBlank;
>  	ControlList ctrls(controls::controls);
>
>  	for (auto const &algo : algorithms_)
> -		algo->process(context_, &frameContext, stats);
> +		algo->process(context_, frameContext, stats);
>
>  	setControls(frame);
>
> @@ -590,11 +590,11 @@ void IPAIPU3::processStatsBuffer(const uint32_t frame,
>  	int64_t frameDuration = (vBlank + sensorInfo_.outputSize.height) * lineDuration;
>  	ctrls.set(controls::FrameDuration, frameDuration);
>
> -	ctrls.set(controls::AnalogueGain, frameContext.sensor.gain);
> +	ctrls.set(controls::AnalogueGain, frameContext->sensor.gain);
>
>  	ctrls.set(controls::ColourTemperature, context_.activeState.awb.temperatureK);
>
> -	ctrls.set(controls::ExposureTime, frameContext.sensor.exposure * lineDuration);
> +	ctrls.set(controls::ExposureTime, frameContext->sensor.exposure * lineDuration);
>
>  	/*
>  	 * \todo The Metadata provides a path to getting extended data
> --
> 2.31.1
>

Hi Jacopo

On 6/8/22 14:04, Jacopo Mondi wrote:
> Hi Umang,
>
> On Fri, Jun 03, 2022 at 03:22:56PM +0200, Umang Jain via libcamera-devel wrote:
>> There are cases where we need more checks and balance to be carried out
>> by the frame context queue class. For that, separate it out as a
>> distinct class on which we can build upon.
>>
>> For now, a minimialistic implementation is provided with .get(frame)
>> helper which returns a IPAFrameContext pointer for the required frame.
>> Going ahead more such helpers can be provided to access/modify the
>> frame context queue.
>>
>> Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
>> Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
>> Reviewed-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
>> ---
>>   src/ipa/ipu3/ipa_context.cpp | 57 ++++++++++++++++++++++++++++++++++--
>>   src/ipa/ipu3/ipa_context.h   | 11 ++++++-
>>   src/ipa/ipu3/ipu3.cpp        | 18 ++++++------
>>   3 files changed, 74 insertions(+), 12 deletions(-)
>>
>> diff --git a/src/ipa/ipu3/ipa_context.cpp b/src/ipa/ipu3/ipa_context.cpp
>> index 13cdb835..9f95a61c 100644
>> --- a/src/ipa/ipu3/ipa_context.cpp
>> +++ b/src/ipa/ipu3/ipa_context.cpp
>> @@ -7,12 +7,18 @@
>>
>>   #include "ipa_context.h"
>>
>> +#include <libcamera/base/log.h>
>> +
>>   /**
>>    * \file ipa_context.h
>>    * \brief Context and state information shared between the algorithms
>>    */
>>
>> -namespace libcamera::ipa::ipu3 {
>> +namespace libcamera {
>> +
>> +LOG_DECLARE_CATEGORY(IPAIPU3)
>> +
>> +namespace ipa::ipu3 {
>>
>>   /**
>>    * \struct IPASessionConfiguration
>> @@ -211,4 +217,51 @@ IPAFrameContext::IPAFrameContext(uint32_t id, const ControlList &reqControls)
>>    * \brief Analogue gain multiplier
>>    */
>>
>> -} /* namespace libcamera::ipa::ipu3 */
>> +/**
>> + * \class FCQueue
>> + * \brief A FIFO circular queue holding IPAFrameContext(s)
>> + *
>> + * FCQueue holds all the IPAFrameContext(s) related to frames required
>> + * to be processed by the IPA at a given point.
>> + */
>> +
>> +/**
>> + * \brief FCQueue constructor
>> + */
>> +FCQueue::FCQueue()
>> +{
>> +	clear();
>> +}
>> +
>> +/**
>> + * \brief Retrieve the IPAFrameContext for the frame
>> + * \param[in] frame Frame number for which the IPAFrameContext needs to
>> + * retrieved
>> + *
>> + * \return Pointer to the IPAFrameContext
>> + */
>> +IPAFrameContext *FCQueue::get(uint32_t frame)
>> +{
>> +	IPAFrameContext &frameContext = this->at(frame % kMaxFrameContexts);
>> +
>> +	if (frame != frameContext.frame) {
>> +		LOG(IPAIPU3, Warning)
>> +			<< "Got wrong frame context for frame" << frame
>> +			<< " or frame context doesn't exist yet";
>> +	}
>> +
>> +	return &frameContext;
>> +}
>> +
>> +/**
>> + * \brief Clear the FCQueue by resetting all the entries in the ring-buffer
>> + */
>> +void FCQueue::clear()
>> +{
>> +	IPAFrameContext initFrameContext;
>> +	this->fill(initFrameContext);
>> +}
>> +
>> +} /* namespace ipa::ipu3 */
>> +
>> +} /* namespace libcamera */
>> diff --git a/src/ipa/ipu3/ipa_context.h b/src/ipa/ipu3/ipa_context.h
>> index 42e11141..56d281f6 100644
>> --- a/src/ipa/ipu3/ipa_context.h
>> +++ b/src/ipa/ipu3/ipa_context.h
>> @@ -89,11 +89,20 @@ struct IPAFrameContext {
>>   	ControlList frameControls;
>>   };
>>
>> +class FCQueue : public std::array<IPAFrameContext, kMaxFrameContexts>
> This will expose the full std::array<> interface.
> I wonder if this should not rather inherit std::array<> as private and
> selectively expose only certain functions. That's what ControlInfoMap
> does, as an example.


Ah correct, I don't want to expose the entire std::array<> interface.

If you have seen I disable the [] operator in 2/3 but still .at() is 
exposed.
So better to inherit it as private. I'll checkout ControlInfoMap.

>
> Then the next question is if we want to have a circular buffer class
> in libcamera and make
>
> class FCQueue : public libcamera::CircualBuffer<IPAFrameContext, kMaxFrameContexts>
> {
>
> }


Feels a bit early, as I have mentioned before. The design discussion is 
still
underway it seems (thanks to your reviews), which I assumed was solidified
already (my mistake probably)

Now if it seems they aren't, putting something generic in libcamera core for
this purpose - doesn't seem to be a good idea to me because we will probably
end up customizing the "generic" CircularBuffer to suit the needs of IPA 
- which
will be living in libcamera-core. I probably resist doing it *for now*, 
until we have
a clear idea of the design needs (and putting a design where other IPAs 
can use it
hopefully).

I get the temptation to do it generically, but I suppose the priority at 
the moment
is get build a support layer for 'per-frame' controls. Get it working on 
one platform,
then pull out the parts to make it generic - without regressing PFC. 
Does this sound
good?

>
>> +{
>> +public:
>> +	FCQueue();
>> +
>> +	void clear();
>> +	IPAFrameContext *get(uint32_t frame);
>> +};
>> +
>>   struct IPAContext {
>>   	IPASessionConfiguration configuration;
>>   	IPAActiveState activeState;
>>
>> -	std::array<IPAFrameContext, kMaxFrameContexts> frameContexts;
>> +	FCQueue frameContexts;
>>   };
>>
>>   } /* namespace ipa::ipu3 */
>> diff --git a/src/ipa/ipu3/ipu3.cpp b/src/ipa/ipu3/ipu3.cpp
>> index 2f6bb672..0843d882 100644
>> --- a/src/ipa/ipu3/ipu3.cpp
>> +++ b/src/ipa/ipu3/ipu3.cpp
>> @@ -456,8 +456,8 @@ int IPAIPU3::configure(const IPAConfigInfo &configInfo,
>>
>>   	/* Clean IPAActiveState at each reconfiguration. */
>>   	context_.activeState = {};
>> -	IPAFrameContext initFrameContext;
>> -	context_.frameContexts.fill(initFrameContext);
>> +	context_.frameContexts.clear();
>> +
> Unecessary empty line
>
>>   	if (!validateSensorControls()) {
>>   		LOG(IPAIPU3, Error) << "Sensor control validation failed.";
>> @@ -569,20 +569,20 @@ void IPAIPU3::processStatsBuffer(const uint32_t frame,
>>   	const ipu3_uapi_stats_3a *stats =
>>   		reinterpret_cast<ipu3_uapi_stats_3a *>(mem.data());
>>
>> -	IPAFrameContext &frameContext = context_.frameContexts[frame % kMaxFrameContexts];
>> +	IPAFrameContext *frameContext = context_.frameContexts.get(frame);
>>
>> -	if (frameContext.frame != frame)
>> +	if (frameContext->frame != frame)
>>   		LOG(IPAIPU3, Warning) << "Frame " << frame << " does not match its frame context";
>>
>> -	frameContext.sensor.exposure = sensorControls.get(V4L2_CID_EXPOSURE).get<int32_t>();
>> -	frameContext.sensor.gain = camHelper_->gain(sensorControls.get(V4L2_CID_ANALOGUE_GAIN).get<int32_t>());
>> +	frameContext->sensor.exposure = sensorControls.get(V4L2_CID_EXPOSURE).get<int32_t>();
>> +	frameContext->sensor.gain = camHelper_->gain(sensorControls.get(V4L2_CID_ANALOGUE_GAIN).get<int32_t>());
>>
>>   	double lineDuration = context_.configuration.sensor.lineDuration.get<std::micro>();
>>   	int32_t vBlank = context_.configuration.sensor.defVBlank;
>>   	ControlList ctrls(controls::controls);
>>
>>   	for (auto const &algo : algorithms_)
>> -		algo->process(context_, &frameContext, stats);
>> +		algo->process(context_, frameContext, stats);
>>
>>   	setControls(frame);
>>
>> @@ -590,11 +590,11 @@ void IPAIPU3::processStatsBuffer(const uint32_t frame,
>>   	int64_t frameDuration = (vBlank + sensorInfo_.outputSize.height) * lineDuration;
>>   	ctrls.set(controls::FrameDuration, frameDuration);
>>
>> -	ctrls.set(controls::AnalogueGain, frameContext.sensor.gain);
>> +	ctrls.set(controls::AnalogueGain, frameContext->sensor.gain);
>>
>>   	ctrls.set(controls::ColourTemperature, context_.activeState.awb.temperatureK);
>>
>> -	ctrls.set(controls::ExposureTime, frameContext.sensor.exposure * lineDuration);
>> +	ctrls.set(controls::ExposureTime, frameContext->sensor.exposure * lineDuration);
>>
>>   	/*
>>   	 * \todo The Metadata provides a path to getting extended data
>> --
>> 2.31.1
>>

Hi Umang,

On Thu, Jun 09, 2022 at 11:13:01AM +0200, Umang Jain wrote:
> Hi Jacopo
>
> On 6/8/22 14:04, Jacopo Mondi wrote:
> > Hi Umang,
> >
> > On Fri, Jun 03, 2022 at 03:22:56PM +0200, Umang Jain via libcamera-devel wrote:
> > > There are cases where we need more checks and balance to be carried out
> > > by the frame context queue class. For that, separate it out as a
> > > distinct class on which we can build upon.
> > >
> > > For now, a minimialistic implementation is provided with .get(frame)
> > > helper which returns a IPAFrameContext pointer for the required frame.
> > > Going ahead more such helpers can be provided to access/modify the
> > > frame context queue.
> > >
> > > Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
> > > Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
> > > Reviewed-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
> > > ---
> > >   src/ipa/ipu3/ipa_context.cpp | 57 ++++++++++++++++++++++++++++++++++--
> > >   src/ipa/ipu3/ipa_context.h   | 11 ++++++-
> > >   src/ipa/ipu3/ipu3.cpp        | 18 ++++++------
> > >   3 files changed, 74 insertions(+), 12 deletions(-)
> > >
> > > diff --git a/src/ipa/ipu3/ipa_context.cpp b/src/ipa/ipu3/ipa_context.cpp
> > > index 13cdb835..9f95a61c 100644
> > > --- a/src/ipa/ipu3/ipa_context.cpp
> > > +++ b/src/ipa/ipu3/ipa_context.cpp
> > > @@ -7,12 +7,18 @@
> > >
> > >   #include "ipa_context.h"
> > >
> > > +#include <libcamera/base/log.h>
> > > +
> > >   /**
> > >    * \file ipa_context.h
> > >    * \brief Context and state information shared between the algorithms
> > >    */
> > >
> > > -namespace libcamera::ipa::ipu3 {
> > > +namespace libcamera {
> > > +
> > > +LOG_DECLARE_CATEGORY(IPAIPU3)
> > > +
> > > +namespace ipa::ipu3 {
> > >
> > >   /**
> > >    * \struct IPASessionConfiguration
> > > @@ -211,4 +217,51 @@ IPAFrameContext::IPAFrameContext(uint32_t id, const ControlList &reqControls)
> > >    * \brief Analogue gain multiplier
> > >    */
> > >
> > > -} /* namespace libcamera::ipa::ipu3 */
> > > +/**
> > > + * \class FCQueue
> > > + * \brief A FIFO circular queue holding IPAFrameContext(s)
> > > + *
> > > + * FCQueue holds all the IPAFrameContext(s) related to frames required
> > > + * to be processed by the IPA at a given point.
> > > + */
> > > +
> > > +/**
> > > + * \brief FCQueue constructor
> > > + */
> > > +FCQueue::FCQueue()
> > > +{
> > > +	clear();
> > > +}
> > > +
> > > +/**
> > > + * \brief Retrieve the IPAFrameContext for the frame
> > > + * \param[in] frame Frame number for which the IPAFrameContext needs to
> > > + * retrieved
> > > + *
> > > + * \return Pointer to the IPAFrameContext
> > > + */
> > > +IPAFrameContext *FCQueue::get(uint32_t frame)
> > > +{
> > > +	IPAFrameContext &frameContext = this->at(frame % kMaxFrameContexts);
> > > +
> > > +	if (frame != frameContext.frame) {
> > > +		LOG(IPAIPU3, Warning)
> > > +			<< "Got wrong frame context for frame" << frame
> > > +			<< " or frame context doesn't exist yet";
> > > +	}
> > > +
> > > +	return &frameContext;
> > > +}
> > > +
> > > +/**
> > > + * \brief Clear the FCQueue by resetting all the entries in the ring-buffer
> > > + */
> > > +void FCQueue::clear()
> > > +{
> > > +	IPAFrameContext initFrameContext;
> > > +	this->fill(initFrameContext);
> > > +}
> > > +
> > > +} /* namespace ipa::ipu3 */
> > > +
> > > +} /* namespace libcamera */
> > > diff --git a/src/ipa/ipu3/ipa_context.h b/src/ipa/ipu3/ipa_context.h
> > > index 42e11141..56d281f6 100644
> > > --- a/src/ipa/ipu3/ipa_context.h
> > > +++ b/src/ipa/ipu3/ipa_context.h
> > > @@ -89,11 +89,20 @@ struct IPAFrameContext {
> > >   	ControlList frameControls;
> > >   };
> > >
> > > +class FCQueue : public std::array<IPAFrameContext, kMaxFrameContexts>
> > This will expose the full std::array<> interface.
> > I wonder if this should not rather inherit std::array<> as private and
> > selectively expose only certain functions. That's what ControlInfoMap
> > does, as an example.
>
>
> Ah correct, I don't want to expose the entire std::array<> interface.
>
> If you have seen I disable the [] operator in 2/3 but still .at() is
> exposed.
> So better to inherit it as private. I'll checkout ControlInfoMap.
>
> >
> > Then the next question is if we want to have a circular buffer class
> > in libcamera and make
> >
> > class FCQueue : public libcamera::CircualBuffer<IPAFrameContext, kMaxFrameContexts>
> > {
> >
> > }
>
>
> Feels a bit early, as I have mentioned before. The design discussion is
> still
> underway it seems (thanks to your reviews), which I assumed was solidified
> already (my mistake probably)

Sorry, I didn't want to question already agreed design decision, but
looks like 2/4 needs some rework anyway, and there might be ways to
make the implementation more robust

>
> Now if it seems they aren't, putting something generic in libcamera core for
> this purpose - doesn't seem to be a good idea to me because we will probably
> end up customizing the "generic" CircularBuffer to suit the needs of IPA -
> which
> will be living in libcamera-core. I probably resist doing it *for now*,
> until we have
> a clear idea of the design needs (and putting a design where other IPAs can
> use it
> hopefully).

I was thinking mostly about DelayedControls that currently implements
a circular array too, but I agree more users might help solidify the
design

>
> I get the temptation to do it generically, but I suppose the priority at the
> moment
> is get build a support layer for 'per-frame' controls. Get it working on one
> platform,
> then pull out the parts to make it generic - without regressing PFC. Does
> this sound
> good?

Yes, let's clarify 2/4 and get this one done!

Thanks
   j

>
> >
> > > +{
> > > +public:
> > > +	FCQueue();
> > > +
> > > +	void clear();
> > > +	IPAFrameContext *get(uint32_t frame);
> > > +};
> > > +
> > >   struct IPAContext {
> > >   	IPASessionConfiguration configuration;
> > >   	IPAActiveState activeState;
> > >
> > > -	std::array<IPAFrameContext, kMaxFrameContexts> frameContexts;
> > > +	FCQueue frameContexts;
> > >   };
> > >
> > >   } /* namespace ipa::ipu3 */
> > > diff --git a/src/ipa/ipu3/ipu3.cpp b/src/ipa/ipu3/ipu3.cpp
> > > index 2f6bb672..0843d882 100644
> > > --- a/src/ipa/ipu3/ipu3.cpp
> > > +++ b/src/ipa/ipu3/ipu3.cpp
> > > @@ -456,8 +456,8 @@ int IPAIPU3::configure(const IPAConfigInfo &configInfo,
> > >
> > >   	/* Clean IPAActiveState at each reconfiguration. */
> > >   	context_.activeState = {};
> > > -	IPAFrameContext initFrameContext;
> > > -	context_.frameContexts.fill(initFrameContext);
> > > +	context_.frameContexts.clear();
> > > +
> > Unecessary empty line
> >
> > >   	if (!validateSensorControls()) {
> > >   		LOG(IPAIPU3, Error) << "Sensor control validation failed.";
> > > @@ -569,20 +569,20 @@ void IPAIPU3::processStatsBuffer(const uint32_t frame,
> > >   	const ipu3_uapi_stats_3a *stats =
> > >   		reinterpret_cast<ipu3_uapi_stats_3a *>(mem.data());
> > >
> > > -	IPAFrameContext &frameContext = context_.frameContexts[frame % kMaxFrameContexts];
> > > +	IPAFrameContext *frameContext = context_.frameContexts.get(frame);
> > >
> > > -	if (frameContext.frame != frame)
> > > +	if (frameContext->frame != frame)
> > >   		LOG(IPAIPU3, Warning) << "Frame " << frame << " does not match its frame context";
> > >
> > > -	frameContext.sensor.exposure = sensorControls.get(V4L2_CID_EXPOSURE).get<int32_t>();
> > > -	frameContext.sensor.gain = camHelper_->gain(sensorControls.get(V4L2_CID_ANALOGUE_GAIN).get<int32_t>());
> > > +	frameContext->sensor.exposure = sensorControls.get(V4L2_CID_EXPOSURE).get<int32_t>();
> > > +	frameContext->sensor.gain = camHelper_->gain(sensorControls.get(V4L2_CID_ANALOGUE_GAIN).get<int32_t>());
> > >
> > >   	double lineDuration = context_.configuration.sensor.lineDuration.get<std::micro>();
> > >   	int32_t vBlank = context_.configuration.sensor.defVBlank;
> > >   	ControlList ctrls(controls::controls);
> > >
> > >   	for (auto const &algo : algorithms_)
> > > -		algo->process(context_, &frameContext, stats);
> > > +		algo->process(context_, frameContext, stats);
> > >
> > >   	setControls(frame);
> > >
> > > @@ -590,11 +590,11 @@ void IPAIPU3::processStatsBuffer(const uint32_t frame,
> > >   	int64_t frameDuration = (vBlank + sensorInfo_.outputSize.height) * lineDuration;
> > >   	ctrls.set(controls::FrameDuration, frameDuration);
> > >
> > > -	ctrls.set(controls::AnalogueGain, frameContext.sensor.gain);
> > > +	ctrls.set(controls::AnalogueGain, frameContext->sensor.gain);
> > >
> > >   	ctrls.set(controls::ColourTemperature, context_.activeState.awb.temperatureK);
> > >
> > > -	ctrls.set(controls::ExposureTime, frameContext.sensor.exposure * lineDuration);
> > > +	ctrls.set(controls::ExposureTime, frameContext->sensor.exposure * lineDuration);
> > >
> > >   	/*
> > >   	 * \todo The Metadata provides a path to getting extended data
> > > --
> > > 2.31.1
> > >