[libcamera-devel,RFC,v2,1/2] qcam: format_converter: put parameters of different formats into union

Message ID 20200908150739.1552-2-andrey.konovalov@linaro.org
State Superseded
Delegated to: Laurent Pinchart
Headers show
Series
  • qcam: format_converter: add 10 and 12 bit packed raw Bayer formats
Related show

Commit Message

Andrey Konovalov Sept. 8, 2020, 3:07 p.m. UTC
As the number of supported formats in the converter grows, having the
format-specific parameters in a union makes the code cleaner, and save
some amount of memory.

Signed-off-by: Andrey Konovalov <andrey.konovalov@linaro.org>
---
 src/qcam/format_converter.cpp | 133 ++++++++++++++++++----------------
 src/qcam/format_converter.h   |  37 ++++++----
 2 files changed, 92 insertions(+), 78 deletions(-)

Comments

Laurent Pinchart Sept. 12, 2020, 12:44 a.m. UTC | #1
Hi Andrey,

Thank you for the patch.

On Tue, Sep 08, 2020 at 06:07:38PM +0300, Andrey Konovalov wrote:
> As the number of supported formats in the converter grows, having the
> format-specific parameters in a union makes the code cleaner, and save
> some amount of memory.
>
> Signed-off-by: Andrey Konovalov <andrey.konovalov@linaro.org>
> ---
>  src/qcam/format_converter.cpp | 133 ++++++++++++++++++----------------
>  src/qcam/format_converter.h   |  37 ++++++----
>  2 files changed, 92 insertions(+), 78 deletions(-)
> 
> diff --git a/src/qcam/format_converter.cpp b/src/qcam/format_converter.cpp
> index 4b9722d..3481330 100644
> --- a/src/qcam/format_converter.cpp
> +++ b/src/qcam/format_converter.cpp
> @@ -33,103 +33,103 @@ int FormatConverter::configure(const libcamera::PixelFormat &format,
>  	switch (format) {
>  	case libcamera::formats::NV12:
>  		formatFamily_ = NV;
> -		horzSubSample_ = 2;
> -		vertSubSample_ = 2;
> -		nvSwap_ = false;
> +		params_.nv.horzSubSample = 2;
> +		params_.nv.vertSubSample = 2;
> +		params_.nv.nvSwap = false;
>  		break;
>  	case libcamera::formats::NV21:
>  		formatFamily_ = NV;
> -		horzSubSample_ = 2;
> -		vertSubSample_ = 2;
> -		nvSwap_ = true;
> +		params_.nv.horzSubSample = 2;
> +		params_.nv.vertSubSample = 2;
> +		params_.nv.nvSwap = true;
>  		break;
>  	case libcamera::formats::NV16:
>  		formatFamily_ = NV;
> -		horzSubSample_ = 2;
> -		vertSubSample_ = 1;
> -		nvSwap_ = false;
> +		params_.nv.horzSubSample = 2;
> +		params_.nv.vertSubSample = 1;
> +		params_.nv.nvSwap = false;
>  		break;
>  	case libcamera::formats::NV61:
>  		formatFamily_ = NV;
> -		horzSubSample_ = 2;
> -		vertSubSample_ = 1;
> -		nvSwap_ = true;
> +		params_.nv.horzSubSample = 2;
> +		params_.nv.vertSubSample = 1;
> +		params_.nv.nvSwap = true;
>  		break;
>  	case libcamera::formats::NV24:
>  		formatFamily_ = NV;
> -		horzSubSample_ = 1;
> -		vertSubSample_ = 1;
> -		nvSwap_ = false;
> +		params_.nv.horzSubSample = 1;
> +		params_.nv.vertSubSample = 1;
> +		params_.nv.nvSwap = false;
>  		break;
>  	case libcamera::formats::NV42:
>  		formatFamily_ = NV;
> -		horzSubSample_ = 1;
> -		vertSubSample_ = 1;
> -		nvSwap_ = true;
> +		params_.nv.horzSubSample = 1;
> +		params_.nv.vertSubSample = 1;
> +		params_.nv.nvSwap = true;
>  		break;
>  
>  	case libcamera::formats::RGB888:
>  		formatFamily_ = RGB;
> -		r_pos_ = 2;
> -		g_pos_ = 1;
> -		b_pos_ = 0;
> -		bpp_ = 3;
> +		params_.rgb.r_pos = 2;
> +		params_.rgb.g_pos = 1;
> +		params_.rgb.b_pos = 0;
> +		params_.rgb.bpp = 3;
>  		break;
>  	case libcamera::formats::BGR888:
>  		formatFamily_ = RGB;
> -		r_pos_ = 0;
> -		g_pos_ = 1;
> -		b_pos_ = 2;
> -		bpp_ = 3;
> +		params_.rgb.r_pos = 0;
> +		params_.rgb.g_pos = 1;
> +		params_.rgb.b_pos = 2;
> +		params_.rgb.bpp = 3;
>  		break;
>  	case libcamera::formats::ARGB8888:
>  		formatFamily_ = RGB;
> -		r_pos_ = 2;
> -		g_pos_ = 1;
> -		b_pos_ = 0;
> -		bpp_ = 4;
> +		params_.rgb.r_pos = 2;
> +		params_.rgb.g_pos = 1;
> +		params_.rgb.b_pos = 0;
> +		params_.rgb.bpp = 4;
>  		break;
>  	case libcamera::formats::RGBA8888:
>  		formatFamily_ = RGB;
> -		r_pos_ = 3;
> -		g_pos_ = 2;
> -		b_pos_ = 1;
> -		bpp_ = 4;
> +		params_.rgb.r_pos = 3;
> +		params_.rgb.g_pos = 2;
> +		params_.rgb.b_pos = 1;
> +		params_.rgb.bpp = 4;
>  		break;
>  	case libcamera::formats::ABGR8888:
>  		formatFamily_ = RGB;
> -		r_pos_ = 0;
> -		g_pos_ = 1;
> -		b_pos_ = 2;
> -		bpp_ = 4;
> +		params_.rgb.r_pos = 0;
> +		params_.rgb.g_pos = 1;
> +		params_.rgb.b_pos = 2;
> +		params_.rgb.bpp = 4;
>  		break;
>  	case libcamera::formats::BGRA8888:
>  		formatFamily_ = RGB;
> -		r_pos_ = 1;
> -		g_pos_ = 2;
> -		b_pos_ = 3;
> -		bpp_ = 4;
> +		params_.rgb.r_pos = 1;
> +		params_.rgb.g_pos = 2;
> +		params_.rgb.b_pos = 3;
> +		params_.rgb.bpp = 4;
>  		break;
>  
>  	case libcamera::formats::VYUY:
>  		formatFamily_ = YUV;
> -		y_pos_ = 1;
> -		cb_pos_ = 2;
> +		params_.yuv.y_pos = 1;
> +		params_.yuv.cb_pos = 2;
>  		break;
>  	case libcamera::formats::YVYU:
>  		formatFamily_ = YUV;
> -		y_pos_ = 0;
> -		cb_pos_ = 3;
> +		params_.yuv.y_pos = 0;
> +		params_.yuv.cb_pos = 3;
>  		break;
>  	case libcamera::formats::UYVY:
>  		formatFamily_ = YUV;
> -		y_pos_ = 1;
> -		cb_pos_ = 0;
> +		params_.yuv.y_pos = 1;
> +		params_.yuv.cb_pos = 0;
>  		break;
>  	case libcamera::formats::YUYV:
>  		formatFamily_ = YUV;
> -		y_pos_ = 0;
> -		cb_pos_ = 1;
> +		params_.yuv.y_pos = 0;
> +		params_.yuv.cb_pos = 1;
>  		break;
>  
>  	case libcamera::formats::MJPEG:
> @@ -178,18 +178,20 @@ static void yuv_to_rgb(int y, int u, int v, int *r, int *g, int *b)
>  
>  void FormatConverter::convertNV(const unsigned char *src, unsigned char *dst)
>  {
> -	unsigned int c_stride = width_ * (2 / horzSubSample_);
> -	unsigned int c_inc = horzSubSample_ == 1 ? 2 : 0;
> -	unsigned int cb_pos = nvSwap_ ? 1 : 0;
> -	unsigned int cr_pos = nvSwap_ ? 0 : 1;
> +	unsigned int c_stride = width_ * (2 / params_.nv.horzSubSample);
> +	unsigned int c_inc = params_.nv.horzSubSample == 1 ? 2 : 0;
> +	unsigned int cb_pos = params_.nv.nvSwap ? 1 : 0;
> +	unsigned int cr_pos = params_.nv.nvSwap ? 0 : 1;
>  	const unsigned char *src_c = src + width_ * height_;
>  	int r, g, b;
>  
>  	for (unsigned int y = 0; y < height_; y++) {
>  		const unsigned char *src_y = src + y * width_;
> -		const unsigned char *src_cb = src_c + (y / vertSubSample_) *
> +		const unsigned char *src_cb = src_c +
> +					      (y / params_.nv.vertSubSample) *
>  					      c_stride + cb_pos;
> -		const unsigned char *src_cr = src_c + (y / vertSubSample_) *
> +		const unsigned char *src_cr = src_c +
> +					      (y / params_.nv.vertSubSample) *
>  					      c_stride + cr_pos;
>  
>  		for (unsigned int x = 0; x < width_; x += 2) {
> @@ -223,9 +225,9 @@ void FormatConverter::convertRGB(const unsigned char *src, unsigned char *dst)
>  
>  	for (y = 0; y < height_; y++) {
>  		for (x = 0; x < width_; x++) {
> -			r = src[bpp_ * x + r_pos_];
> -			g = src[bpp_ * x + g_pos_];
> -			b = src[bpp_ * x + b_pos_];
> +			r = src[params_.rgb.bpp * x + params_.rgb.r_pos];
> +			g = src[params_.rgb.bpp * x + params_.rgb.g_pos];
> +			b = src[params_.rgb.bpp * x + params_.rgb.b_pos];
>  
>  			dst[4 * x + 0] = b;
>  			dst[4 * x + 1] = g;
> @@ -233,7 +235,7 @@ void FormatConverter::convertRGB(const unsigned char *src, unsigned char *dst)
>  			dst[4 * x + 3] = 0xff;
>  		}
>  
> -		src += width_ * bpp_;
> +		src += width_ * params_.rgb.bpp;
>  		dst += width_ * 4;
>  	}
>  }
> @@ -246,16 +248,18 @@ void FormatConverter::convertYUV(const unsigned char *src, unsigned char *dst)
>  	unsigned int cr_pos;
>  	int r, g, b, y, cr, cb;
>  
> -	cr_pos = (cb_pos_ + 2) % 4;
> +	cr_pos = (params_.yuv.cb_pos + 2) % 4;
>  	src_stride = width_ * 2;
>  	dst_stride = width_ * 4;
>  
>  	for (src_y = 0, dst_y = 0; dst_y < height_; src_y++, dst_y++) {
>  		for (src_x = 0, dst_x = 0; dst_x < width_; ) {
> -			cb = src[src_y * src_stride + src_x * 4 + cb_pos_];
> +			cb = src[src_y * src_stride + src_x * 4 +
> +				 params_.yuv.cb_pos];
>  			cr = src[src_y * src_stride + src_x * 4 + cr_pos];
>  
> -			y = src[src_y * src_stride + src_x * 4 + y_pos_];
> +			y = src[src_y * src_stride + src_x * 4 +
> +				params_.yuv.y_pos];
>  			yuv_to_rgb(y, cb, cr, &r, &g, &b);
>  			dst[dst_y * dst_stride + 4 * dst_x + 0] = b;
>  			dst[dst_y * dst_stride + 4 * dst_x + 1] = g;
> @@ -263,7 +267,8 @@ void FormatConverter::convertYUV(const unsigned char *src, unsigned char *dst)
>  			dst[dst_y * dst_stride + 4 * dst_x + 3] = 0xff;
>  			dst_x++;
>  
> -			y = src[src_y * src_stride + src_x * 4 + y_pos_ + 2];
> +			y = src[src_y * src_stride + src_x * 4 +
> +				params_.yuv.y_pos + 2];
>  			yuv_to_rgb(y, cb, cr, &r, &g, &b);
>  			dst[dst_y * dst_stride + 4 * dst_x + 0] = b;
>  			dst[dst_y * dst_stride + 4 * dst_x + 1] = g;
> diff --git a/src/qcam/format_converter.h b/src/qcam/format_converter.h
> index e389b24..c53fa28 100644
> --- a/src/qcam/format_converter.h
> +++ b/src/qcam/format_converter.h
> @@ -40,20 +40,29 @@ private:
>  
>  	enum FormatFamily formatFamily_;
>  
> -	/* NV parameters */
> -	unsigned int horzSubSample_;
> -	unsigned int vertSubSample_;
> -	bool nvSwap_;
> -
> -	/* RGB parameters */
> -	unsigned int bpp_;
> -	unsigned int r_pos_;
> -	unsigned int g_pos_;
> -	unsigned int b_pos_;
> -
> -	/* YUV parameters */
> -	unsigned int y_pos_;
> -	unsigned int cb_pos_;
> +	union {
> +		/* NV parameters */
> +		struct nv_params {
> +			unsigned int horzSubSample;
> +			unsigned int vertSubSample;
> +			bool nvSwap;
> +		} nv;
> +
> +		/* RGB parameters */
> +		struct rgb_params {
> +			unsigned int bpp;
> +			unsigned int r_pos;
> +			unsigned int g_pos;
> +			unsigned int b_pos;
> +		} rgb;
> +
> +		/* YUV parameters */
> +		struct yuv_params {
> +			unsigned int y_pos;
> +			unsigned int cb_pos;
> +		} yuv;

The NV* formats are YUV too, we should try to find a better name. It's a
pre-existing issue though.

> +	} params_;

I wonder if it wouldn't make more sense to move all of these to a
separate structure, stored in a map indexed by the pixel format. That
would greatly simplify FormatConverter::configure(). We actually have
such a structure already, PixelFormatInfo, but it's an internal API.
Exposing it as a public API runs into the issue that not all the fields
it contains should be exposed. The V4L2 4CC, for instance, should stay
internal. There's probably a way to handle that, but I'm also no really
keen at this point to committing to a stable API for PixelFormatInfo. I
thus think it would be better to duplicate the data we need here.

To avoid blocking Bayer support in qcam on this, how about moving
forward with patch 2/2 for now without 1/2 ? The small space increase is
negligible.

> +

Extra blank line.

>  };
>  
>  #endif /* __QCAM_FORMAT_CONVERTER_H__ */
Andrey Konovalov Sept. 22, 2020, 8:03 p.m. UTC | #2
Hi Laurent,

Thanks for the review.

On 12.09.2020 03:44, Laurent Pinchart wrote:
> Hi Andrey,
> 
> Thank you for the patch.
> 
> On Tue, Sep 08, 2020 at 06:07:38PM +0300, Andrey Konovalov wrote:
>> As the number of supported formats in the converter grows, having the
>> format-specific parameters in a union makes the code cleaner, and save
>> some amount of memory.
>>
>> Signed-off-by: Andrey Konovalov <andrey.konovalov@linaro.org>
>> ---
>>   src/qcam/format_converter.cpp | 133 ++++++++++++++++++----------------
>>   src/qcam/format_converter.h   |  37 ++++++----
>>   2 files changed, 92 insertions(+), 78 deletions(-)
>>
>> diff --git a/src/qcam/format_converter.cpp b/src/qcam/format_converter.cpp
>> index 4b9722d..3481330 100644
>> --- a/src/qcam/format_converter.cpp
>> +++ b/src/qcam/format_converter.cpp
>> @@ -33,103 +33,103 @@ int FormatConverter::configure(const libcamera::PixelFormat &format,
>>   	switch (format) {
>>   	case libcamera::formats::NV12:
>>   		formatFamily_ = NV;
>> -		horzSubSample_ = 2;
>> -		vertSubSample_ = 2;
>> -		nvSwap_ = false;
>> +		params_.nv.horzSubSample = 2;
>> +		params_.nv.vertSubSample = 2;
>> +		params_.nv.nvSwap = false;
>>   		break;
>>   	case libcamera::formats::NV21:
>>   		formatFamily_ = NV;
>> -		horzSubSample_ = 2;
>> -		vertSubSample_ = 2;
>> -		nvSwap_ = true;
>> +		params_.nv.horzSubSample = 2;
>> +		params_.nv.vertSubSample = 2;
>> +		params_.nv.nvSwap = true;
>>   		break;
>>   	case libcamera::formats::NV16:
>>   		formatFamily_ = NV;
>> -		horzSubSample_ = 2;
>> -		vertSubSample_ = 1;
>> -		nvSwap_ = false;
>> +		params_.nv.horzSubSample = 2;
>> +		params_.nv.vertSubSample = 1;
>> +		params_.nv.nvSwap = false;
>>   		break;
>>   	case libcamera::formats::NV61:
>>   		formatFamily_ = NV;
>> -		horzSubSample_ = 2;
>> -		vertSubSample_ = 1;
>> -		nvSwap_ = true;
>> +		params_.nv.horzSubSample = 2;
>> +		params_.nv.vertSubSample = 1;
>> +		params_.nv.nvSwap = true;
>>   		break;
>>   	case libcamera::formats::NV24:
>>   		formatFamily_ = NV;
>> -		horzSubSample_ = 1;
>> -		vertSubSample_ = 1;
>> -		nvSwap_ = false;
>> +		params_.nv.horzSubSample = 1;
>> +		params_.nv.vertSubSample = 1;
>> +		params_.nv.nvSwap = false;
>>   		break;
>>   	case libcamera::formats::NV42:
>>   		formatFamily_ = NV;
>> -		horzSubSample_ = 1;
>> -		vertSubSample_ = 1;
>> -		nvSwap_ = true;
>> +		params_.nv.horzSubSample = 1;
>> +		params_.nv.vertSubSample = 1;
>> +		params_.nv.nvSwap = true;
>>   		break;
>>   
>>   	case libcamera::formats::RGB888:
>>   		formatFamily_ = RGB;
>> -		r_pos_ = 2;
>> -		g_pos_ = 1;
>> -		b_pos_ = 0;
>> -		bpp_ = 3;
>> +		params_.rgb.r_pos = 2;
>> +		params_.rgb.g_pos = 1;
>> +		params_.rgb.b_pos = 0;
>> +		params_.rgb.bpp = 3;
>>   		break;
>>   	case libcamera::formats::BGR888:
>>   		formatFamily_ = RGB;
>> -		r_pos_ = 0;
>> -		g_pos_ = 1;
>> -		b_pos_ = 2;
>> -		bpp_ = 3;
>> +		params_.rgb.r_pos = 0;
>> +		params_.rgb.g_pos = 1;
>> +		params_.rgb.b_pos = 2;
>> +		params_.rgb.bpp = 3;
>>   		break;
>>   	case libcamera::formats::ARGB8888:
>>   		formatFamily_ = RGB;
>> -		r_pos_ = 2;
>> -		g_pos_ = 1;
>> -		b_pos_ = 0;
>> -		bpp_ = 4;
>> +		params_.rgb.r_pos = 2;
>> +		params_.rgb.g_pos = 1;
>> +		params_.rgb.b_pos = 0;
>> +		params_.rgb.bpp = 4;
>>   		break;
>>   	case libcamera::formats::RGBA8888:
>>   		formatFamily_ = RGB;
>> -		r_pos_ = 3;
>> -		g_pos_ = 2;
>> -		b_pos_ = 1;
>> -		bpp_ = 4;
>> +		params_.rgb.r_pos = 3;
>> +		params_.rgb.g_pos = 2;
>> +		params_.rgb.b_pos = 1;
>> +		params_.rgb.bpp = 4;
>>   		break;
>>   	case libcamera::formats::ABGR8888:
>>   		formatFamily_ = RGB;
>> -		r_pos_ = 0;
>> -		g_pos_ = 1;
>> -		b_pos_ = 2;
>> -		bpp_ = 4;
>> +		params_.rgb.r_pos = 0;
>> +		params_.rgb.g_pos = 1;
>> +		params_.rgb.b_pos = 2;
>> +		params_.rgb.bpp = 4;
>>   		break;
>>   	case libcamera::formats::BGRA8888:
>>   		formatFamily_ = RGB;
>> -		r_pos_ = 1;
>> -		g_pos_ = 2;
>> -		b_pos_ = 3;
>> -		bpp_ = 4;
>> +		params_.rgb.r_pos = 1;
>> +		params_.rgb.g_pos = 2;
>> +		params_.rgb.b_pos = 3;
>> +		params_.rgb.bpp = 4;
>>   		break;
>>   
>>   	case libcamera::formats::VYUY:
>>   		formatFamily_ = YUV;
>> -		y_pos_ = 1;
>> -		cb_pos_ = 2;
>> +		params_.yuv.y_pos = 1;
>> +		params_.yuv.cb_pos = 2;
>>   		break;
>>   	case libcamera::formats::YVYU:
>>   		formatFamily_ = YUV;
>> -		y_pos_ = 0;
>> -		cb_pos_ = 3;
>> +		params_.yuv.y_pos = 0;
>> +		params_.yuv.cb_pos = 3;
>>   		break;
>>   	case libcamera::formats::UYVY:
>>   		formatFamily_ = YUV;
>> -		y_pos_ = 1;
>> -		cb_pos_ = 0;
>> +		params_.yuv.y_pos = 1;
>> +		params_.yuv.cb_pos = 0;
>>   		break;
>>   	case libcamera::formats::YUYV:
>>   		formatFamily_ = YUV;
>> -		y_pos_ = 0;
>> -		cb_pos_ = 1;
>> +		params_.yuv.y_pos = 0;
>> +		params_.yuv.cb_pos = 1;
>>   		break;
>>   
>>   	case libcamera::formats::MJPEG:
>> @@ -178,18 +178,20 @@ static void yuv_to_rgb(int y, int u, int v, int *r, int *g, int *b)
>>   
>>   void FormatConverter::convertNV(const unsigned char *src, unsigned char *dst)
>>   {
>> -	unsigned int c_stride = width_ * (2 / horzSubSample_);
>> -	unsigned int c_inc = horzSubSample_ == 1 ? 2 : 0;
>> -	unsigned int cb_pos = nvSwap_ ? 1 : 0;
>> -	unsigned int cr_pos = nvSwap_ ? 0 : 1;
>> +	unsigned int c_stride = width_ * (2 / params_.nv.horzSubSample);
>> +	unsigned int c_inc = params_.nv.horzSubSample == 1 ? 2 : 0;
>> +	unsigned int cb_pos = params_.nv.nvSwap ? 1 : 0;
>> +	unsigned int cr_pos = params_.nv.nvSwap ? 0 : 1;
>>   	const unsigned char *src_c = src + width_ * height_;
>>   	int r, g, b;
>>   
>>   	for (unsigned int y = 0; y < height_; y++) {
>>   		const unsigned char *src_y = src + y * width_;
>> -		const unsigned char *src_cb = src_c + (y / vertSubSample_) *
>> +		const unsigned char *src_cb = src_c +
>> +					      (y / params_.nv.vertSubSample) *
>>   					      c_stride + cb_pos;
>> -		const unsigned char *src_cr = src_c + (y / vertSubSample_) *
>> +		const unsigned char *src_cr = src_c +
>> +					      (y / params_.nv.vertSubSample) *
>>   					      c_stride + cr_pos;
>>   
>>   		for (unsigned int x = 0; x < width_; x += 2) {
>> @@ -223,9 +225,9 @@ void FormatConverter::convertRGB(const unsigned char *src, unsigned char *dst)
>>   
>>   	for (y = 0; y < height_; y++) {
>>   		for (x = 0; x < width_; x++) {
>> -			r = src[bpp_ * x + r_pos_];
>> -			g = src[bpp_ * x + g_pos_];
>> -			b = src[bpp_ * x + b_pos_];
>> +			r = src[params_.rgb.bpp * x + params_.rgb.r_pos];
>> +			g = src[params_.rgb.bpp * x + params_.rgb.g_pos];
>> +			b = src[params_.rgb.bpp * x + params_.rgb.b_pos];
>>   
>>   			dst[4 * x + 0] = b;
>>   			dst[4 * x + 1] = g;
>> @@ -233,7 +235,7 @@ void FormatConverter::convertRGB(const unsigned char *src, unsigned char *dst)
>>   			dst[4 * x + 3] = 0xff;
>>   		}
>>   
>> -		src += width_ * bpp_;
>> +		src += width_ * params_.rgb.bpp;
>>   		dst += width_ * 4;
>>   	}
>>   }
>> @@ -246,16 +248,18 @@ void FormatConverter::convertYUV(const unsigned char *src, unsigned char *dst)
>>   	unsigned int cr_pos;
>>   	int r, g, b, y, cr, cb;
>>   
>> -	cr_pos = (cb_pos_ + 2) % 4;
>> +	cr_pos = (params_.yuv.cb_pos + 2) % 4;
>>   	src_stride = width_ * 2;
>>   	dst_stride = width_ * 4;
>>   
>>   	for (src_y = 0, dst_y = 0; dst_y < height_; src_y++, dst_y++) {
>>   		for (src_x = 0, dst_x = 0; dst_x < width_; ) {
>> -			cb = src[src_y * src_stride + src_x * 4 + cb_pos_];
>> +			cb = src[src_y * src_stride + src_x * 4 +
>> +				 params_.yuv.cb_pos];
>>   			cr = src[src_y * src_stride + src_x * 4 + cr_pos];
>>   
>> -			y = src[src_y * src_stride + src_x * 4 + y_pos_];
>> +			y = src[src_y * src_stride + src_x * 4 +
>> +				params_.yuv.y_pos];
>>   			yuv_to_rgb(y, cb, cr, &r, &g, &b);
>>   			dst[dst_y * dst_stride + 4 * dst_x + 0] = b;
>>   			dst[dst_y * dst_stride + 4 * dst_x + 1] = g;
>> @@ -263,7 +267,8 @@ void FormatConverter::convertYUV(const unsigned char *src, unsigned char *dst)
>>   			dst[dst_y * dst_stride + 4 * dst_x + 3] = 0xff;
>>   			dst_x++;
>>   
>> -			y = src[src_y * src_stride + src_x * 4 + y_pos_ + 2];
>> +			y = src[src_y * src_stride + src_x * 4 +
>> +				params_.yuv.y_pos + 2];
>>   			yuv_to_rgb(y, cb, cr, &r, &g, &b);
>>   			dst[dst_y * dst_stride + 4 * dst_x + 0] = b;
>>   			dst[dst_y * dst_stride + 4 * dst_x + 1] = g;
>> diff --git a/src/qcam/format_converter.h b/src/qcam/format_converter.h
>> index e389b24..c53fa28 100644
>> --- a/src/qcam/format_converter.h
>> +++ b/src/qcam/format_converter.h
>> @@ -40,20 +40,29 @@ private:
>>   
>>   	enum FormatFamily formatFamily_;
>>   
>> -	/* NV parameters */
>> -	unsigned int horzSubSample_;
>> -	unsigned int vertSubSample_;
>> -	bool nvSwap_;
>> -
>> -	/* RGB parameters */
>> -	unsigned int bpp_;
>> -	unsigned int r_pos_;
>> -	unsigned int g_pos_;
>> -	unsigned int b_pos_;
>> -
>> -	/* YUV parameters */
>> -	unsigned int y_pos_;
>> -	unsigned int cb_pos_;
>> +	union {
>> +		/* NV parameters */
>> +		struct nv_params {
>> +			unsigned int horzSubSample;
>> +			unsigned int vertSubSample;
>> +			bool nvSwap;
>> +		} nv;
>> +
>> +		/* RGB parameters */
>> +		struct rgb_params {
>> +			unsigned int bpp;
>> +			unsigned int r_pos;
>> +			unsigned int g_pos;
>> +			unsigned int b_pos;
>> +		} rgb;
>> +
>> +		/* YUV parameters */
>> +		struct yuv_params {
>> +			unsigned int y_pos;
>> +			unsigned int cb_pos;
>> +		} yuv;
> 
> The NV* formats are YUV too, we should try to find a better name. It's a
> pre-existing issue though.
> 
>> +	} params_;
> 
> I wonder if it wouldn't make more sense to move all of these to a
> separate structure, stored in a map indexed by the pixel format. That
> would greatly simplify FormatConverter::configure(). We actually have
> such a structure already, PixelFormatInfo, but it's an internal API.
> Exposing it as a public API runs into the issue that not all the fields
> it contains should be exposed. The V4L2 4CC, for instance, should stay
> internal. There's probably a way to handle that, but I'm also no really
> keen at this point to committing to a stable API for PixelFormatInfo. I
> thus think it would be better to duplicate the data we need here.

Yes, this makes sense, and will probably take some more patch review
iterations.

> To avoid blocking Bayer support in qcam on this, how about moving
> forward with patch 2/2 for now without 1/2 ? The small space increase is
> negligible.

That's fine for me. Let's go this way.

In this case should I still use:

	/* RAW Bayer parameters */
	struct bayer_params {
		/*
		 * Bytes per pixel is a fractional number, and is
		 * represented by integer numerator and denominator.
		 */
		unsigned int bpp_numer;
		unsigned int bpp_denom;
		unsigned int r_pos;
		/*
		 * The fields below are used to hold the values computed
		 * in configure() based on r_pos and width_.
		 */
		unsigned int g1_pos;
		unsigned int g2_pos;
		unsigned int b_pos;
		unsigned int srcLineLength;
	} bayer_;

- as the member of FormatConverter (all Bayer parameters grouped together into one member),
or should I follow the current pattern and make each of the above parameters a separate member of
FormatConverter (and invent some other name for r_pos_ and b_pos_ not to clash with the existing
RGB parameters)?

Thanks,
Andrey

>> +
> 
> Extra blank line.
> 
>>   };
>>   
>>   #endif /* __QCAM_FORMAT_CONVERTER_H__ */
>

Patch

diff --git a/src/qcam/format_converter.cpp b/src/qcam/format_converter.cpp
index 4b9722d..3481330 100644
--- a/src/qcam/format_converter.cpp
+++ b/src/qcam/format_converter.cpp
@@ -33,103 +33,103 @@  int FormatConverter::configure(const libcamera::PixelFormat &format,
 	switch (format) {
 	case libcamera::formats::NV12:
 		formatFamily_ = NV;
-		horzSubSample_ = 2;
-		vertSubSample_ = 2;
-		nvSwap_ = false;
+		params_.nv.horzSubSample = 2;
+		params_.nv.vertSubSample = 2;
+		params_.nv.nvSwap = false;
 		break;
 	case libcamera::formats::NV21:
 		formatFamily_ = NV;
-		horzSubSample_ = 2;
-		vertSubSample_ = 2;
-		nvSwap_ = true;
+		params_.nv.horzSubSample = 2;
+		params_.nv.vertSubSample = 2;
+		params_.nv.nvSwap = true;
 		break;
 	case libcamera::formats::NV16:
 		formatFamily_ = NV;
-		horzSubSample_ = 2;
-		vertSubSample_ = 1;
-		nvSwap_ = false;
+		params_.nv.horzSubSample = 2;
+		params_.nv.vertSubSample = 1;
+		params_.nv.nvSwap = false;
 		break;
 	case libcamera::formats::NV61:
 		formatFamily_ = NV;
-		horzSubSample_ = 2;
-		vertSubSample_ = 1;
-		nvSwap_ = true;
+		params_.nv.horzSubSample = 2;
+		params_.nv.vertSubSample = 1;
+		params_.nv.nvSwap = true;
 		break;
 	case libcamera::formats::NV24:
 		formatFamily_ = NV;
-		horzSubSample_ = 1;
-		vertSubSample_ = 1;
-		nvSwap_ = false;
+		params_.nv.horzSubSample = 1;
+		params_.nv.vertSubSample = 1;
+		params_.nv.nvSwap = false;
 		break;
 	case libcamera::formats::NV42:
 		formatFamily_ = NV;
-		horzSubSample_ = 1;
-		vertSubSample_ = 1;
-		nvSwap_ = true;
+		params_.nv.horzSubSample = 1;
+		params_.nv.vertSubSample = 1;
+		params_.nv.nvSwap = true;
 		break;
 
 	case libcamera::formats::RGB888:
 		formatFamily_ = RGB;
-		r_pos_ = 2;
-		g_pos_ = 1;
-		b_pos_ = 0;
-		bpp_ = 3;
+		params_.rgb.r_pos = 2;
+		params_.rgb.g_pos = 1;
+		params_.rgb.b_pos = 0;
+		params_.rgb.bpp = 3;
 		break;
 	case libcamera::formats::BGR888:
 		formatFamily_ = RGB;
-		r_pos_ = 0;
-		g_pos_ = 1;
-		b_pos_ = 2;
-		bpp_ = 3;
+		params_.rgb.r_pos = 0;
+		params_.rgb.g_pos = 1;
+		params_.rgb.b_pos = 2;
+		params_.rgb.bpp = 3;
 		break;
 	case libcamera::formats::ARGB8888:
 		formatFamily_ = RGB;
-		r_pos_ = 2;
-		g_pos_ = 1;
-		b_pos_ = 0;
-		bpp_ = 4;
+		params_.rgb.r_pos = 2;
+		params_.rgb.g_pos = 1;
+		params_.rgb.b_pos = 0;
+		params_.rgb.bpp = 4;
 		break;
 	case libcamera::formats::RGBA8888:
 		formatFamily_ = RGB;
-		r_pos_ = 3;
-		g_pos_ = 2;
-		b_pos_ = 1;
-		bpp_ = 4;
+		params_.rgb.r_pos = 3;
+		params_.rgb.g_pos = 2;
+		params_.rgb.b_pos = 1;
+		params_.rgb.bpp = 4;
 		break;
 	case libcamera::formats::ABGR8888:
 		formatFamily_ = RGB;
-		r_pos_ = 0;
-		g_pos_ = 1;
-		b_pos_ = 2;
-		bpp_ = 4;
+		params_.rgb.r_pos = 0;
+		params_.rgb.g_pos = 1;
+		params_.rgb.b_pos = 2;
+		params_.rgb.bpp = 4;
 		break;
 	case libcamera::formats::BGRA8888:
 		formatFamily_ = RGB;
-		r_pos_ = 1;
-		g_pos_ = 2;
-		b_pos_ = 3;
-		bpp_ = 4;
+		params_.rgb.r_pos = 1;
+		params_.rgb.g_pos = 2;
+		params_.rgb.b_pos = 3;
+		params_.rgb.bpp = 4;
 		break;
 
 	case libcamera::formats::VYUY:
 		formatFamily_ = YUV;
-		y_pos_ = 1;
-		cb_pos_ = 2;
+		params_.yuv.y_pos = 1;
+		params_.yuv.cb_pos = 2;
 		break;
 	case libcamera::formats::YVYU:
 		formatFamily_ = YUV;
-		y_pos_ = 0;
-		cb_pos_ = 3;
+		params_.yuv.y_pos = 0;
+		params_.yuv.cb_pos = 3;
 		break;
 	case libcamera::formats::UYVY:
 		formatFamily_ = YUV;
-		y_pos_ = 1;
-		cb_pos_ = 0;
+		params_.yuv.y_pos = 1;
+		params_.yuv.cb_pos = 0;
 		break;
 	case libcamera::formats::YUYV:
 		formatFamily_ = YUV;
-		y_pos_ = 0;
-		cb_pos_ = 1;
+		params_.yuv.y_pos = 0;
+		params_.yuv.cb_pos = 1;
 		break;
 
 	case libcamera::formats::MJPEG:
@@ -178,18 +178,20 @@  static void yuv_to_rgb(int y, int u, int v, int *r, int *g, int *b)
 
 void FormatConverter::convertNV(const unsigned char *src, unsigned char *dst)
 {
-	unsigned int c_stride = width_ * (2 / horzSubSample_);
-	unsigned int c_inc = horzSubSample_ == 1 ? 2 : 0;
-	unsigned int cb_pos = nvSwap_ ? 1 : 0;
-	unsigned int cr_pos = nvSwap_ ? 0 : 1;
+	unsigned int c_stride = width_ * (2 / params_.nv.horzSubSample);
+	unsigned int c_inc = params_.nv.horzSubSample == 1 ? 2 : 0;
+	unsigned int cb_pos = params_.nv.nvSwap ? 1 : 0;
+	unsigned int cr_pos = params_.nv.nvSwap ? 0 : 1;
 	const unsigned char *src_c = src + width_ * height_;
 	int r, g, b;
 
 	for (unsigned int y = 0; y < height_; y++) {
 		const unsigned char *src_y = src + y * width_;
-		const unsigned char *src_cb = src_c + (y / vertSubSample_) *
+		const unsigned char *src_cb = src_c +
+					      (y / params_.nv.vertSubSample) *
 					      c_stride + cb_pos;
-		const unsigned char *src_cr = src_c + (y / vertSubSample_) *
+		const unsigned char *src_cr = src_c +
+					      (y / params_.nv.vertSubSample) *
 					      c_stride + cr_pos;
 
 		for (unsigned int x = 0; x < width_; x += 2) {
@@ -223,9 +225,9 @@  void FormatConverter::convertRGB(const unsigned char *src, unsigned char *dst)
 
 	for (y = 0; y < height_; y++) {
 		for (x = 0; x < width_; x++) {
-			r = src[bpp_ * x + r_pos_];
-			g = src[bpp_ * x + g_pos_];
-			b = src[bpp_ * x + b_pos_];
+			r = src[params_.rgb.bpp * x + params_.rgb.r_pos];
+			g = src[params_.rgb.bpp * x + params_.rgb.g_pos];
+			b = src[params_.rgb.bpp * x + params_.rgb.b_pos];
 
 			dst[4 * x + 0] = b;
 			dst[4 * x + 1] = g;
@@ -233,7 +235,7 @@  void FormatConverter::convertRGB(const unsigned char *src, unsigned char *dst)
 			dst[4 * x + 3] = 0xff;
 		}
 
-		src += width_ * bpp_;
+		src += width_ * params_.rgb.bpp;
 		dst += width_ * 4;
 	}
 }
@@ -246,16 +248,18 @@  void FormatConverter::convertYUV(const unsigned char *src, unsigned char *dst)
 	unsigned int cr_pos;
 	int r, g, b, y, cr, cb;
 
-	cr_pos = (cb_pos_ + 2) % 4;
+	cr_pos = (params_.yuv.cb_pos + 2) % 4;
 	src_stride = width_ * 2;
 	dst_stride = width_ * 4;
 
 	for (src_y = 0, dst_y = 0; dst_y < height_; src_y++, dst_y++) {
 		for (src_x = 0, dst_x = 0; dst_x < width_; ) {
-			cb = src[src_y * src_stride + src_x * 4 + cb_pos_];
+			cb = src[src_y * src_stride + src_x * 4 +
+				 params_.yuv.cb_pos];
 			cr = src[src_y * src_stride + src_x * 4 + cr_pos];
 
-			y = src[src_y * src_stride + src_x * 4 + y_pos_];
+			y = src[src_y * src_stride + src_x * 4 +
+				params_.yuv.y_pos];
 			yuv_to_rgb(y, cb, cr, &r, &g, &b);
 			dst[dst_y * dst_stride + 4 * dst_x + 0] = b;
 			dst[dst_y * dst_stride + 4 * dst_x + 1] = g;
@@ -263,7 +267,8 @@  void FormatConverter::convertYUV(const unsigned char *src, unsigned char *dst)
 			dst[dst_y * dst_stride + 4 * dst_x + 3] = 0xff;
 			dst_x++;
 
-			y = src[src_y * src_stride + src_x * 4 + y_pos_ + 2];
+			y = src[src_y * src_stride + src_x * 4 +
+				params_.yuv.y_pos + 2];
 			yuv_to_rgb(y, cb, cr, &r, &g, &b);
 			dst[dst_y * dst_stride + 4 * dst_x + 0] = b;
 			dst[dst_y * dst_stride + 4 * dst_x + 1] = g;
diff --git a/src/qcam/format_converter.h b/src/qcam/format_converter.h
index e389b24..c53fa28 100644
--- a/src/qcam/format_converter.h
+++ b/src/qcam/format_converter.h
@@ -40,20 +40,29 @@  private:
 
 	enum FormatFamily formatFamily_;
 
-	/* NV parameters */
-	unsigned int horzSubSample_;
-	unsigned int vertSubSample_;
-	bool nvSwap_;
-
-	/* RGB parameters */
-	unsigned int bpp_;
-	unsigned int r_pos_;
-	unsigned int g_pos_;
-	unsigned int b_pos_;
-
-	/* YUV parameters */
-	unsigned int y_pos_;
-	unsigned int cb_pos_;
+	union {
+		/* NV parameters */
+		struct nv_params {
+			unsigned int horzSubSample;
+			unsigned int vertSubSample;
+			bool nvSwap;
+		} nv;
+
+		/* RGB parameters */
+		struct rgb_params {
+			unsigned int bpp;
+			unsigned int r_pos;
+			unsigned int g_pos;
+			unsigned int b_pos;
+		} rgb;
+
+		/* YUV parameters */
+		struct yuv_params {
+			unsigned int y_pos;
+			unsigned int cb_pos;
+		} yuv;
+	} params_;
+
 };
 
 #endif /* __QCAM_FORMAT_CONVERTER_H__ */