I've downloaded and compiled the vaapi plugin set, and for some specific cases it works great, but it also breaks many of my existing pipelines. I'd like to modify Gstreamer to use other decoders first.
Is there a way to alter the rank of Gstreamer plugins without modifying the original sources?
I don't see a means of doing this at a configuration level in the Gstreamer registry file. This code does the trick though:
GstRegistry* reg = gst_registry_get();
GstPluginFeature* vaapi_decode = gst_registry_lookup_feature(reg, "vaapidecode");
if(vaapi_decode == NULL) {
return;
}
gst_plugin_feature_set_rank(vaapi_decode, GST_RANK_PRIMARY - 1);
gst_object_unref(vaapi_decode);
I hold a volume image in a vtkImageData and need to convert it to DcmDataset (DCMTK). I know that I need to set general DICOM tags like patient data to the data set. That's not the problem.
Especially I'm interested in putting the pixel data to DcmDataset. Does anybody know an example or can explain how to do that?
Thanks in advance
Quoting from the DCMTK FAQ:
Is there a tool that converts common graphic formats like PGM/PPM,
PNG, TIFF, JPEG or BMP to DICOM?
No, unfortunately, there is no such tool in DCMTK. Currently, you have to write your own little program for that purpose.
The following code snippet from the toolkit's documentation could be a starting point:
char uid[100];
DcmFileFormat fileformat;
DcmDataset *dataset = fileformat.getDataset();
dataset->putAndInsertString(DCM_SOPClassUID, UID_SecondaryCaptureImageStorage);
dataset->putAndInsertString(DCM_SOPInstanceUID, dcmGenerateUniqueIdentifier(uid, SITE_INSTANCE_UID_ROOT));
dataset->putAndInsertString(DCM_PatientsName, "Doe^John");
/* ... */
dataset->putAndInsertUint8Array(DCM_PixelData, pixelData, pixelLength);
OFCondition status = fileformat.saveFile("test.dcm", EXS_LittleEndianExplicit);
if (status.bad())
cerr << "Error: cannot write DICOM file (" << status.text() << ")" << endl;
The current snapshot of the DCMTK (> version 3.5.4) contains a new
command line tool "img2dcm" that allows for converting JPEG images to
certain DICOM image SOP classes.
I would perhaps look first at the source code for img2dcm (documented here) to see the general process and then post back with any specific questions. IMHO, DCMTK is very powerful but extremely difficult to understand.
I use GStreamer on Windows VS 2010 and need a pair Camera names - camera ID. Like logitech ... - sdjvnskj (or any other way to have an ID for a camera) and ID should be like in Linux /dev/video0,1 ... . I'm using the ways like ylatuya offerd How to detect the device name for a capture device? but it returns half of a string Ok - "USB" and half - UTF unreadable rubish (or mayb) like "\xe0Y\xd2". I have some examples from Linux where after it they create a pipeline like
GstElement *pipeline = gst_parse_launch("dshowvideosrc device-name="+ gst_camera_capturer_enum_video_devices() +"name=source1 ! ffmpegcolorspace ! fakesink", NULL);
but in device-name they write "/dev/video" and I don't know what to write for it. Also how to add to gchar something from GList? I just then need to get resolutions and framerates for each cameras.
Ok. If it's needed to anybody except me than the pair like in linux ID ("/dev/video0") and normal name is a bit difficult to get. In my case it shows only "USB-video device" for all cameras which is as I understand an ID and the symbolic name at the same time. Just put it to device-name=
in GstElement *pipeline = gst_parse_launch(
like above and you have the right camera that you need. The question here is :
"Does win differs cameras by anything except it's path or ID in dshow???".
Also I write in Russian OS and with Russian VS 2010 so the question is
how to print everything in Russian if in the line "USB-video device" USB prints ok and the rest, which is in Russian, is a useless line of some strange symbols?
But when I print it to a file it's ok.
I am writing a small program to let me switch my resolution back and forth because my projector cannot handle the same resolution as my screen. I already know how to set the screen resolution using the windows API. As well as read the current resolution using the windows API or the QT4 toolkit. My problem is I want a menu of all of the different resolutions supported by the screen and graphics card. This program will be distributed so I need the program to actually communicate to the graphics card to find out what it supports. The only API I want to use is the windows API, or the QT4 toolkit, but I don't think QT4 does that unless you are using the graphics widgets in odd ways.
I am pretty sure this is possible with the WINDOWS API. I just don't know how to do it.
Oh and please cut me some slack, I am familiar with QT4 and C++ but I am typically a Linux programmer, I am writing this for someone else. The only thing I have ever done with the windows API is make a message box, set the background, and used system variables. So please explain the process simply. Please don't just post a link to the msdn, I hate their documentation, and I hate Microsoft. I use windows maybe twice a year.
The following should probably work for you in the general case
DEVMODE dm = { 0 };
dm.dmSize = sizeof(dm);
for( int iModeNum = 0; EnumDisplaySettings( NULL, iModeNum, &dm ) != 0; iModeNum++ ) {
cout << "Mode #" << iModeNum << " = " << dm.dmPelsWidth << "x" << dm.dmPelsHeight << endl;
}
This should print out all the supported resolutions on the current display that the .exe is running on. Assuming you're not dealing with a multi-display graphics card this should work. Otherwise you'd have to use EnumDisplayDevices loop over each display.
Once you figure out what resolution you want you can use 'ChangeDisplaySettingsEx' to change the display to the mode you want.
Using DirectX is possible but I wouldn't recommend it as the code is alot more complicated (having to initialize DirectX and using COM pointers) unless you plan to actually use DirectX for more than just determining display resolutions.
EnumDisplaySettings :)
From MSDN:
"To obtain the current display settings, pass the ENUM_CURRENT_SETTINGS constant in the iModeNum parameter to the EnumDisplaySettings API, as illustrated by the following C++ code."
DEVMODE dm;
// initialize the DEVMODE structure
ZeroMemory(&dm, sizeof(dm));
dm.dmSize = sizeof(dm);
if (0 != EnumDisplaySettings(NULL, ENUM_CURRENT_SETTINGS, &dm))
{
// inspect the DEVMODE structure to obtain details
// about the display settings such as
// - Orientation
// - Width and Height
// - Frequency
// - etc.
}
I would like to open a small video file and map every frames in memory (to apply some custom filter). I don't want to handle the video codec, I would rather let the library handle that for me.
I've tried to use Direct Show with the SampleGrabber filter (using this sample http://msdn.microsoft.com/en-us/library/ms787867(VS.85).aspx), but I only managed to grab some frames (not every frames!). I'm quite new in video software programming, maybe I'm not using the best library, or I'm doing it wrong.
I've pasted a part of my code (mainly a modified copy/paste from the msdn example), unfortunately it doesn't grabb the 25 first frames as expected...
[...]
hr = pGrabber->SetOneShot(TRUE);
hr = pGrabber->SetBufferSamples(TRUE);
pControl->Run(); // Run the graph.
pEvent->WaitForCompletion(INFINITE, &evCode); // Wait till it's done.
// Find the required buffer size.
long cbBuffer = 0;
hr = pGrabber->GetCurrentBuffer(&cbBuffer, NULL);
for( int i = 0 ; i < 25 ; ++i )
{
pControl->Run(); // Run the graph.
pEvent->WaitForCompletion(INFINITE, &evCode); // Wait till it's done.
char *pBuffer = new char[cbBuffer];
hr = pGrabber->GetCurrentBuffer(&cbBuffer, (long*)pBuffer);
AM_MEDIA_TYPE mt;
hr = pGrabber->GetConnectedMediaType(&mt);
VIDEOINFOHEADER *pVih;
pVih = (VIDEOINFOHEADER*)mt.pbFormat;
[...]
}
[...]
Is there somebody, with video software experience, who can advise me about code or other simpler library?
Thanks
Edit:
Msdn links seems not to work (see the bug)
Currently these are the most popular video frameworks available on Win32 platforms:
Video for Windows: old windows framework coming from the age of Win95 but still widely used because it is very simple to use. Unfortunately it supports only AVI files for which the proper VFW codec has been installed.
DirectShow: standard WinXP framework, it can basically load all formats you can play with Windows Media Player. Rather difficult to use.
Ffmpeg: more precisely libavcodec and libavformat that comes with Ffmpeg open- source multimedia utility. It is extremely powerful and can read a lot of formats (almost everything you can play with VLC) even if you don't have the codec installed on the system. It's quite complicated to use but you can always get inspired by the code of ffplay that comes shipped with it or by other implementations in open-source software. Anyway I think it's still much easier to use than DS (and much faster). It needs to be comipled by MinGW on Windows, but all the steps are explained very well here (in this moment the link is down, hope not dead).
QuickTime: the Apple framework is not the best solution for Windows platform, since it needs QuickTime app to be installed and also the proper QuickTime codec for every format; it does not support many formats, but its quite common in professional field (so some codec are actually only for QuickTime). Shouldn't be too difficult to implement.
Gstreamer: latest open source framework. I don't know much about it, I guess it wraps over some of the other systems (but I'm not sure).
All of this frameworks have been implemented as backend in OpenCv Highgui, except for DirectShow. The default framework for Win32 OpenCV is using VFW (and thus able only to open some AVI files), if you want to use the others you must download the CVS instead of the official release and still do some hacking on the code and it's anyway not too complete, for example FFMPEG backend doesn't allow to seek in the stream.
If you want to use QuickTime with OpenCV this can help you.
I have used OpenCV to load video files and process them. It's also handy for many types of video processing including those useful for computer vision.
Using the "Callback" model of SampleGrabber may give you better results. See the example in Samples\C++\DirectShow\Editing\GrabBitmaps.
There's also a lot of info in Samples\C++\DirectShow\Filters\Grabber2\grabber_text.txt and readme.txt.
I know it is very tempting in C++ to get a proper breakdown of the video files and just do it yourself. But although the information is out there, it is such a long winded process building classes to hand each file format, and make it easily alterable to take future structure changes into account, that frankly it just is not worth the effort.
Instead I recommend ffmpeg. It got a mention above, but says it is difficult, it isn't difficult. There are a lot more options than most people would need which makes it look more difficult than it is. For the majority of operations you can just let ffmpeg work it out for itself.
For example a file conversion
ffmpeg -i inputFile.mp4 outputFile.avi
Decide right from the start that you will have ffmpeg operations run in a thread, or more precisely a thread library. But have your own thread class wrap it so that you can have your own EventAgs and methods of checking the thread is finished. Something like :-
ThreadLibManager()
{
List<MyThreads> listOfActiveThreads;
public AddThread(MyThreads);
}
Your thread class is something like:-
class MyThread
{
public Thread threadForThisInstance { get; set; }
public MyFFMpegTools mpegTools { get; set; }
}
MyFFMpegTools performs many different video operations, so you want your own event
args to tell your parent code precisely what type of operation has just raised and
event.
enum MyFmpegArgs
{
public int thisThreadID { get; set; } //Set as a new MyThread is added to the List<>
public MyFfmpegType operationType {get; set;}
//output paths etc that the parent handler will need to find output files
}
enum MyFfmpegType
{
FF_CONVERTFILE = 0, FF_CREATETHUMBNAIL, FF_EXTRACTFRAMES ...
}
Here is a small snippet of my ffmpeg tool class, this part collecting information about a video.
I put FFmpeg in a particular location, and at the start of the software running it makes sure that it is there. For this version I have moved it to the Desktop, I am fairly sure I have written the path correctly for you (I really hate MS's special folders system, so I ignore it as much as I can).
Anyway, it is an example of using windowless ffmpeg.
public string GetVideoInfo(FileInfo fi)
{
outputBuilder.Clear();
string strCommand = string.Concat(" -i \"", fi.FullName, "\"");
string ffPath =
System.Environment.GetFolderPath(Environment.SpecialFolder.Desktop) + "\\ffmpeg.exe";
string oStr = "";
try
{
Process build = new Process();
//build.StartInfo.WorkingDirectory = #"dir";
build.StartInfo.Arguments = strCommand;
build.StartInfo.FileName = ffPath;
build.StartInfo.UseShellExecute = false;
build.StartInfo.RedirectStandardOutput = true;
build.StartInfo.RedirectStandardError = true;
build.StartInfo.CreateNoWindow = true;
build.ErrorDataReceived += build_ErrorDataReceived;
build.OutputDataReceived += build_ErrorDataReceived;
build.EnableRaisingEvents = true;
build.Start();
build.BeginOutputReadLine();
build.BeginErrorReadLine();
build.WaitForExit();
string findThis = "start";
int offset = 0;
foreach (string str in outputBuilder)
{
if (str.Contains("Duration"))
{
offset = str.IndexOf(findThis);
oStr = str.Substring(0, offset);
}
}
}
catch
{
oStr = "Error collecting file information";
}
return oStr;
}
private void build_ErrorDataReceived(object sender, DataReceivedEventArgs e)
{
string strMessage = e.Data;
if (outputBuilder != null && strMessage != null)
{
outputBuilder.Add(string.Concat(strMessage, "\n"));
}
}
Try using the OpenCV library. It definitely has the capabilities you require.
This guide has a section about accessing frames from a video file.
If it's for AVI files I'd read the data from the AVI file myself and extract the frames. Now use the video compression manager to decompress it.
The AVI file format is very simple, see: http://msdn.microsoft.com/en-us/library/dd318187(VS.85).aspx (and use google).
Once you have the file open you just extract each frame and pass it to ICDecompress() to decompress it.
It seems like a lot of work but it's the most reliable way.
If that's too much work, or if you want more than AVI files then use ffmpeg.
OpenCV is the best solution if video in your case only needs to lead to a sequence of pictures. If you're willing to do real video processing, so ViDeo equals "Visual Audio", you need to keep up track with the ones offered by "martjno". New windows solutions also for Win7 include 3 new possibilities additionally:
Windows Media Foundation: Successor of DirectShow; cleaned-up interface
Windows Media Encoder 9: It does not only include the programm, it also ships libraries for coding
Windows Expression 4: Successor of 2.
Last 2 are commercial-only solutions, but the first one is free. To code WMF, you need to install the Windows SDK.
I would recommend FFMPEG or GStreamer. Try and stay away from openCV unless you plan to utilize some other functionality than just streaming video. The library is a beefy build and a pain to install from source to configure FFMPEG/+GStreamer options.