Hi
We would like to control viewfinder/preview resolution to avoid unnecessary scaling of viewfinder video stream/preview image. For example in our case we want show the viewfinder in fullscreen mode. For example N900 has screen resolution 840x480. Qt Mobility's camera backend doesn't define viewfinder resolution at all and default resolution 640x400 is used (in case of GStreamer camerabin backend). Yes, the videosurface used to render the viewfinder stream scales the video for fullscreen resolution. We would like avoid that because it possible to define viewfinder resolution to camera backend, at least in case camerabin backend. The same applies for preview (or snapshot) picture. Br, Joonas -----Original Message----- From: qt-mobility-feedback-bounces+joonas.tanskanen=sasken....@qt.nokia.com [mailto:[email protected] a.com] On Behalf Of [email protected] Sent: 24. helmikuuta 2011 9:37 To: [email protected]; [email protected] Subject: Re: [Qt-mobility-feedback] Adding support for settingviewfinder and preview image resolution to Camera API Hi, And to add to Dmytro's comments; Viewfinder: I would see 2 different use cases for viewfinder: * Showing the preview * Providing frames for processing In the first case you probably should not care about the native size of the viewfinder. You're just happy to see it resized based on the QVideoWidget/QGraphicsVideoItem size. In the latter case you probably want to control the viewfinder size, and you can do that with setNativeResolution() of the QAbstractVideoSurface that you gave to QVideoRendererControl. Is your use case somehow different from these? And if yes; Could you describe that in more detail. I think that would help to understand the need for the new API. Preview Image (aka Snapshot): There's already been some initial discussion to include this into some future release of QtMobility. There's no item in Jira at the moment, but feel free create a suggestion of that. Having many thumbs up for that will not at least slow down the process... BR, Tuomas -----Original Message----- From: qt-mobility-feedback-bounces+tuomas.viitanen=nokia....@qt.nokia.com [mailto:[email protected]. com] On Behalf Of Poplavskiy Dmytro (Nokia-MS/Brisbane) Sent: 24.02.2011 08:59 To: [email protected] Subject: Re: [Qt-mobility-feedback] Adding support for setting viewfinder and preview image resolution to Camera API Hi Joonas, On Fri, 18 Feb 2011 02:30:49 am ext Joonas Tanskanen wrote: > Hi > > > I have some questions for Camera API maintainers. > > I found that Camera API doesn't provide way to set viewfinder resolution or preview image resolution. Do you have any plans to add support for these features? We need these features for reference camera application which I am implementing for meego handset platform. I thought that maybe I could add support for these features by myself. > It's useful to specify the viewfinder and image preview resolutions, but the supportes (and efficiently supported) set of resolutions is likely to be limited, it's not very clear how to express such limitations in QCamera APIs. For example in video recording mode the capture resolution/rate matches the viefinder one. One possible solution to have this feature supported right now is to add extra properties to QCameraControl (viewfinderResolution/rate) and QCameraImageCapture (preview resolution property) of camerabin backend. It's possible to do without breaking BC and find what is necessary/suitable and quite easy to implement on backend side. > > My plan is following: > > > 1. add new methods to QCameraImageCapture for setting preview image resolution and viewfinder resolution: > > > QImageEncoderSettings previewSettings() const; > void setPreviewSettings(const QImageEncoderSettings& settings); > > QVideoEncoderSettings viewfinderSettings() const; > void setViewfinderSettings(const QVideoEncoderSettings& settings); > > > > 2. Implement QMediaControl plugins QCameraViewfinderControl and QCameraViewfinderControl. These are used to transfer preview image and viewfinder settings to camera backend. > > > > 3. Modify CameraBinSession to set preview and viewfinder caps to camerabin. > > > > I am able to implement support for camerabin backend only. In case of other backends(s60, mediacapture) setPreviewSettings() and setViewfinderSettings() would do nothing. Is that a problem? It's important to ensure the suitable resolutions is selected when no viewfinder/preview settings are set. > If I implement this change and make a submit request will it be accepted? We need to resolve this problem somehow for MeeGo handset camera UI and I thought that with same effort I could make general solution for this. > If API change required by this is not acceptable we have to consider to implement some kind of meego only solution which doesn't change public API. The API changes should be discussed, since they can't be changes once released, so in the short run it's probably worth to expose a few extra properties of QCameraControl and QCameraImageCapture, and desing the related changes to API once the applications requirements and limitations or expected target platforms are more clear. I'm thinking about extending QCamera API to provide more captured image related metadata (like exposure settings, histogram, etc), preview resolution could be part of those setttings as well. Regards Dmytro. > > Any comments are welcome, especially from Camera API maintainers :) > > > Br, > > Joonas > > > > ________________________________ > SASKEN BUSINESS DISCLAIMER: This message may contain confidential, proprietary or legally privileged information. In case you are not the original intended Recipient of the message, you must not, directly or indirectly, use, disclose, distribute, print, or copy any part of this message and you are requested to delete it and inform the sender. Any views expressed in this message are those of the individual sender unless otherwise stated. Nothing contained in this message shall be construed as an offer or acceptance of any offer by Sasken Communication Technologies Limited ("Sasken") unless sent with that express intent and with due authority of Sasken. Sasken has taken enough precautions to prevent the spread of viruses. However the company accepts no liability for any damage caused by any virus transmitted by this email. > Read Disclaimer at http://www.sasken.com/extras/mail_disclaimer.html > _______________________________________________ Qt-mobility-feedback mailing list [email protected] http://lists.qt.nokia.com/mailman/listinfo/qt-mobility-feedback _______________________________________________ Qt-mobility-feedback mailing list [email protected] http://lists.qt.nokia.com/mailman/listinfo/qt-mobility-feedback _______________________________________________ Qt-mobility-feedback mailing list [email protected] http://lists.qt.nokia.com/mailman/listinfo/qt-mobility-feedback
