[libcamera-devel] [PATCH v3 2/2] android: Fix generation of thumbnail for EXIF data

[Umang Jain]

Hi Paul,

On 9/23/21 3:29 PM, paul.elder at ideasonboard.com wrote:
> Hi Umang,
>
> On Thu, Sep 23, 2021 at 01:23:53PM +0530, Umang Jain wrote:
>> Hi Paul,
>>
>> On 9/23/21 1:10 PM, paul.elder at ideasonboard.com wrote:
>>> Hi Umang,
>>>
>>> On Thu, Sep 23, 2021 at 12:54:53PM +0530, Umang Jain wrote:
>>>> Generation of thumbnail is not occuring currently because
>>>> ANDROID_JPEG_THUMBNAIL_SIZE is not set for request metadata passed
>>>> to PostProcessorJpeg::process(). The commit 1264628d3c92("android:
>>>> jpeg: Configure thumbnailer based on request metadata") introduced
>>>> the mechanism to retrieve the thumbanil size from request metadata,
>>>> however it didn't add the counterpart i.e. inserting the size in
>>>> the request metadata in request metadata template, at the first place.
>>>>
>>>> The patch fixes this issue by setting ANDROID_JPEG_THUMBNAIL_SIZE in
>>>> the request metadata template populated by
>>>> CameraCapabilities::requestTemplatePreview(). The value for
>>>> ANDROID_JPEG_THUMBNAIL_SIZE is set to be the first non-zero size
>>>> reported by static metadata ANDROID_JPEG_AVAILABLE_THUMBNAIL_SIZES.
>>>>
>>>> Fixes: 1264628d3c92("android: jpeg: Configure thumbnailer based on request metadata")
>>>> Signed-off-by: Umang Jain <umang.jain at ideasonboard.com>
>>>> Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
>>>> Reviewed-by: Hirokazu Honda <hiroh at chromium.org>
>>>> ---
>>>>    src/android/camera_capabilities.cpp | 24 +++++++++++++++++++++++-
>>>>    1 file changed, 23 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/src/android/camera_capabilities.cpp b/src/android/camera_capabilities.cpp
>>>> index 238b44db..ba6adf73 100644
>>>> --- a/src/android/camera_capabilities.cpp
>>>> +++ b/src/android/camera_capabilities.cpp
>>>> @@ -1347,7 +1347,7 @@ std::unique_ptr<CameraMetadata> CameraCapabilities::requestTemplatePreview() con
>>>>    	 * CameraMetadata is capable to resize the container on the fly, if the
>>>>    	 * number of entries get exceeded.
>>>>    	 */
>>>> -	auto requestTemplate = std::make_unique<CameraMetadata>(21, 36);
>>>> +	auto requestTemplate = std::make_unique<CameraMetadata>(22, 38);
>>>>    	if (!requestTemplate->isValid()) {
>>>>    		return nullptr;
>>>>    	}
>>>> @@ -1368,6 +1368,28 @@ std::unique_ptr<CameraMetadata> CameraCapabilities::requestTemplatePreview() con
>>>>    	requestTemplate->addEntry(ANDROID_CONTROL_AE_TARGET_FPS_RANGE,
>>>>    				  entry.data.i32, 2);
>>>> +	/*
>>>> +	 * Get thumbnail sizes from static metadata and add the first non-zero
>>>> +	 * size to the template.
>>>> +	 */
>>>> +	found = staticMetadata_->getEntry(ANDROID_JPEG_AVAILABLE_THUMBNAIL_SIZES,
>>>> +					  &entry);
>>>> +	ASSERT(found && entry.count >= 4);
>>>> +	unsigned int j = 0;
>>>> +	while (j < entry.count / 2) {
>>> Since you're incrementing j by 2, shouldn't the limit be entry.count?
>>
>> My understanding is 2 entries make 1 size, no?
>> ANDROID_JPEG_AVAILABLE_THUMBNAIL_SIZES be like for e.g.
>>
>>      {0, 0, w1, h1, w2, h2}
>>
>> So entry.count is 6 but sizes are 3
>>
>> To go to next Size, incremement by 2 so, j += 2
> That's true, but for example:
>
> {0, 0, w1, h1, w2, h2}
>
> Iteration 1: j = 0, so you take [0, 1]; afterward j += 2
> Iteration 2: j = 2, so you take [2, 3]; afterward j += 2
> Iteration 3: j = 4, so you take [4, 5]; afterward j += 2
> Itreation 4: j = 6, fails j < entry.count; skip
>
> If you stop at entry.count / 2 then you'll skip the second half of
> pairs.


Oh, you are correct. I missed to see that somehow :-S

>
>
> Paul
>
>> Does it make sense?
>>
>>
>>>> +		if (entry.data.i32[j] == 0 || entry.data.i32[j + 1] == 0) {
>>>> +			j += 2;
>>>> +			continue;
>>>> +		}
>>>> +
>>>> +		requestTemplate->addEntry(ANDROID_JPEG_THUMBNAIL_SIZE,
>>>> +					  entry.data.i32 + j, 2);
>>>> +		break;
>>>> +	}
>>>> +
>>>> +	requestTemplate->addEntry(ANDROID_JPEG_THUMBNAIL_SIZE,
>>>> +				  entry.data.i32 + 2, 2);
>>> iirc adding an entry that already exists causes weird problems...
>>
>> Ah crap, this should be outside the loop. I am re-assigning it here. Sorry,
>> rebase fiasco it seems.
>>
>>>
>>> Paul
>>>
>>>> +
>>>>    	uint8_t aeMode = ANDROID_CONTROL_AE_MODE_ON;
>>>>    	requestTemplate->addEntry(ANDROID_CONTROL_AE_MODE, aeMode);
>>>> -- 
>>>> 2.31.0
>>>>