http://alexmogurenko.com/blog Blog about site, programming and life Thu, 19 Jan 2012 05:33:13 +0000 http://backend.userland.com/rss092 en Couple months ago I worked on audio conference project... On first view everything looks pretty easy (what you need just capture video/audio compress it and send to destination + all encoders/decoders already implemented), but when firs beta was ready we found million underwater stones, even if my connection is fast enough ... http://alexmogurenko.com/blog/uncategorized/mpeg-1-layer-2-multi-bitrate-audio-encoder/ Not sure about everyone, but lots of programmers from time to time got task that on one of stage require to find maximum from unsorted array/memory/... of data. And the best i was working on detecting microphone sound level. So i received buffer of 16 bit samples and to detect level ... http://alexmogurenko.com/blog/programming/max-word-value-sse2/ HTC provides the simpliest DirectShow driver, that does not allow to chose resolution of frame that we want to grab... does not allow to control flash or autofocus and other available settings that default application allows... Here is first version of HTCCamera class that works directly with driver as result we ... http://alexmogurenko.com/blog/uncategorized/htccamera-v10/ After i added functionality to draw target/rectangle on preview, i received some emails with question how to grab part that exactly in rectagnle. Ok you dont need anything special and any lib, for example you draw target with [csharp] Rect _rect [/csharp] then to grab that part you need: 1. Grab full image [csharp] Bitmap bmp = new ... http://alexmogurenko.com/blog/uncategorized/how-to-get-focusedtargeted-image/ Made some changes in samplegrabber and IGetFrame interface now you can define target position and target type, so new IGetFrame: [csharp] [ComVisible(true), ComImport, Guid("2B21644A-D405-4E27-A51C-A4812bE0CE4C"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] public interface IGetFrame { [PreserveSig] int getFrame(IntPtr pBuff); [PreserveSig] int getSize([Out] out long size); [PreserveSig] int getFrameParams( [Out] out int width, [Out] out int height, [Out] out RawFrameFormat format); [PreserveSig] int drawText( [In] IntPtr ptr, [In] int height, [In] int width); [PreserveSig] int stopDraw(); [PreserveSig] int getGrayScale(IntPtr ptr); [PreserveSig] int getRgb(IntPtr ... http://alexmogurenko.com/blog/programming/more-samplegrabber-chages/ I made some changes in native part of library (Samplegrabber) now we can use up to 3 samplegrabbers in the same time and now you can PIvoke for samplegrabber like in bellow code: [csharp] [DllImport("DirectShowNETCF.Native.dll")] private static extern IntPtr GetBaseFilter(int index); [DllImport("DirectShowNETCF.Native.dll")] private static extern void DeleteBaseFilter(int index); [/csharp] also interface IBaseFrame has been changed: [csharp] [ComVisible(true), ComImport, Guid("2B21644A-D405-4E27-A51C-A4812bE0CE4C"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] public interface ... http://alexmogurenko.com/blog/programming/samplegrabber-changes/ If you ever used DirectShow under windows then you know that if you want draw text on preview you can use VMRRenderer, but windows mobile dont provide any way to draw text on preview :( I see there only 1 way to solve it - Draw text directly on stream, so ... http://alexmogurenko.com/blog/programming/windows-mobiledraw-text-on-preview-or-samplegrabber-and-directshownetcf/ What is SampleGrabber? this is filter (as a rule Transform or TransInPlace) that goes after filter which samples we are going to grab. Why do we need SampleGrabber? 1. In windows mobile this is the fastest way to still images, more than that we still uncompressed images (so we dont loose time ... http://alexmogurenko.com/blog/programming/windows-mobile-capturing-raw-frames-or-samplegrabber-and-directshownetcf/ Most of us who was trying to use DirectShowNETCF found that resolution of stilled image smaller that it could be, for example my device (Samsung i710) got default resolution on still pin 320x240, but i know that it supports resolutions up to 2Mpx. So that should be fixed :) What do ... http://alexmogurenko.com/blog/programming/windows-mobile-changing-still-image-resolution-or-directshownetcf-part-iv/ Ok, most popular question for last week was: "How to still images from windows mobile camera?" I finished my project little bit earlier that i was planing, so i have free time again and looking for job too :) So what do we need? tons extra com interfaces (Ipin, IEnumPins, IEnumFilters, IFileSinkFilter, ... http://alexmogurenko.com/blog/programming/windows-mobilestilling-images-from-camera-c-or-directshow-netcf-part-iii/