So I am generating an uncompressed avi using Media Foundation. The frames of the avi originate from in RAM images which are processed.
I manage to generate an avi file which can be played in our own application and in windows media player without a problem. However, when the avi file is played using VLC we get the message: "Index of the file is missing or broken". We can play as is but we want to get rid of the error message. (We also do the same for the h264 format using Media Foundation and this does not include the problem).
I have researched the problem quite extensive and found a possible explanation of the problem here: https://learn.microsoft.com/en-us/answers/questions/114418/mftranscodecontainertype-avi-not-creating-index.html
Another remarks I saw somewhere is that Media Foundation does have a bug in writing the index but I am not sure about this.
I have not figured out a workaround or solution yet. So hopefully someone over here can help.
To give an idea of how the avi is generated (pseudo code):
MFStartUp()
MFCreateFile(MF_ACCESSMODE_READWRITE, MF_OPENMODE_DELETE_IF_EXIST, MF_FILEFLAGS_NONE, pinnedFilename, &pByteStream);
MFCreateAVIMediaSink(pByteStream, pMediaType, NULL, &pMediaSink);
MFCreateSinkWriterFromMediaSink(pMediaSink, pAttr, pSinkWriter);
pSinkWriter->SetInputMediaType(_videoStreamIndex, spTypeIn, NULL)
pSinkWriter->BeginWriting()
Add Frames
SinkWriter->Finalize()
MFShutdown();
Related
I need your help over a problem I have. Actually, I have a page with a simple embed which displays a PDF file.
I got a request to add another PDF file to the same embed (or at least to do something which would look like it).
I searched some solutions and not finding a simple one, I'm thinking about using iTextSharp to merge both files (by getting their stream from their url), merging them into a new pdf file and display this resulting file into the embed.
But I'm just telling myself it's a bit too much for such a simple modification... And so I'm here asking you if someone would have a better idea ? From what I searched on stackoverflow and google it looks like I will have to take the merge solution but hey, we never know '^^
A simpler option would be to merge the two PDF files using either a free online tool or Adobe Combine Files option and then adding that newly combined PDF to your site. Unless I am missing something, there is no real reason or benefit to do this using code.
I have two AVI videos. one will play in an application i am using and the other will not.
looking at them in Media Player Classic properties, they have exactly the same specifications
Codec : DVSD
Named: DVC/DV
but looking at them in GSpot, I finally found a difference.
the working file uses OpenDML AVI 2.0
whereas the file that will not open uses AVI 1.0
I need to convert one to the other, but i cant find a way to convert from one codec to a different version of the same codec, muchless how to find different editions of the same codec.
If anyone has an idea of how to fix this or what the other differences may be, please let me know.
The application I am trying to open these with only functions on Windows XP if that is any indication of what the problem may be.
using the option "save as old avi format" in VirtualDub solves this problem.
http://www.virtualdub.org/download.html
I'm trying to understand how I can generate a waveform from an audio (or video) file to display to the user.
I've been googling around for quite a while now and can't determine if this is even possible in Qt without using something like FFmpeg. I've seen all of these classes: QMediaPlayer, QMediaContent, QMediaResource, QAudioProbe and experimented with the Qt Media Player Example but am just not seeing where I can access the actual audio buffer.
So I have 2 questions:
Is what I want to do even possible without 3rd party libraries?
If it is possible, can some kind soul outline what I need to read and understand in order to access the audio data
I have tried the suggestions from this question (Audio visualization with QMediaPlayer) but the result of audioProbe->setSource(player) is always false and the method processBuffer never gets called.
audioProbe = new QAudioProbe(this);
bool success = audioProbe->setSource(player);
qDebug() << success;
connect(audioProbe, SIGNAL(audioBufferProbed(QAudioBuffer)), this, SLOT(processBuffer(QAudioBuffer)));
Update: Adding some additional detail in the hope of clarifying things.
For testing/learning I am using the Media Player Example which ships with Qt, so it is set up correctly with Q_OBJECT etc.
For audio, I tested with both .mp3 and .wav files. FWIW, the player example won't play video for some reason (.mp4, .avi were tested)
The player in the code is QMediaPlayer – which inherits from QMediaObject. The example code for the Player class is here. I added my code (in original comment above) right after the player is instantiated. I also tried adding it once media is loaded.
I tried declaring my slot first as private, then as public – either way, it is never called.
Frustrating that such a simple thing is so hard.
Going the "no external library" route will likely just lead to more of a headache and more work than is necessary. The other advantage of going with an established library is you won't be bound to one file format, as not all formats store their data the same way. If the audio format is uncompressed (wav or other) you can read the header until you get to the data chunk. An answer to this question here details this in C. You should be able to get an idea for the file format from this to apply it to another language.
You will want to understand how many channels are in the wav file, bit depth, and also the sampling rate before you can do anything worthwhile with the data. All this info can be grabbed from the header.
It turns out that QAudioProbe is not supported on OSX – the platform I am working on. Took quite a while (a "Qt while. . .") to ferret that info out so I am posting it here explicitly.
See this document for full details: Qt 5.5.0 Multimedia Backends
I´m working on an application based on directshow that has to convert an AVI source file to to an mp4-file that can be played back with Quicktime.
Since 3ivx, according to my web research the most popular way to fulfill this task, has become commercial (and my budget is quite limited), I decided to use a solution based on ffdshow.
I created a simple graph in graphedit, using LAME for audio encoding and GDCL MPEG 4 Multiplexor for the muxing, but everytime I try to play the movie with Quicktime, I´m getting an error indicating a wrong "sample description".
Playback with Windows Media Player is working, except that there is no sound.
My guess is that there´s a problem with the muxer, because every time I try to add audio encoding, graphedit automatically adds an decoder after the encoding unit (see picture link).
http://imageshack.us/photo/my-images/39/graphjrgr.png/
Any ideas on how to integrate ffdshow in a better way, tips for alternative mp4 muxers, or a complete different approach are appreciated!
The GDCL muxer has limited number of audio formats that it supports, probably you should check the source code for the muxer to see if the formats you are using are in fact supported. Basically, you need to choose an audio encoder that the mux recognizes as valid. It might be possible to use GraphEdit to choose different properties for the encoder filter that allow things to work better.
I have had some luck with the Monogram x264(video) and AAC(audio) encoders. See http://blog.monogram.sk/janos/directshow-filters/
Finally, try the debug version of the GDCL mp4 muxer.
Also, you must be aware of MPEG-4 LA licensing requirements for x264 http://www.mpegla.com/main/programs/AVC/Pages/FAQ.aspx
I'm building an application to view pdf's through a browser without the need of a plugin on mobile devices. I tried ImageMagick and ghostscript to covert the pages to images but they are far too large and text becomes unclear. I see website offering a service of converting pdf's into html and do a descent job but I can't find an example of how this is accomplished. Any help is much appreciated. Thanks!
EDIT: I seem to have read the question backwards. In this case it might be best to parse through the PDF and then format some HTML based on what you find. I believe the javapdf option is capable of this, but I haven't used any of these so I am not sure. If worse comes to worst and you can't find software to disassemble a PDF, you might be able to write your own disassembler in Java or PHP by reading the PDF specification. Best of luck!
http://www.adobe.com/devnet/pdf/pdf_reference.html - PDF Specification (Adobe Modified Version, because they are most popular you may want to support their extensions)
-- OLD -- These websites probably write their own proprietary software to do the trick. If you are truly interested in this undertaking, I would suggest parsing the HTML to get the data and style information and using it to format some sort of PDF writer APIs. A quick Google search yields the following: -- END OLD --
http://www.cutepdf.com/Solutions/
http://ruby-pdf.rubyforge.org/pdf-writer/doc/index.html
http://asprise.com/product/javapdf/
If you are looking at converting PDF to HTML and planning to run the conversion on a server, then you can try pdf2html. It is a program packaged as part of poppler-utils. I do not know how the program accomplishes it.
I was googling and came across the below link explaining how scridb.com implements conversion.
http://coding.scribd.com/2010/06/01/the-perils-of-stacking/