I am trying to find duration of an mp4 file using direct show component of windows using the Dotnet wrapper(directShow-lib 2005). But the method i used was GetDuration of IMediaSeeking interface. But this returns zero as duration.
After searching i found the following statement:
"It doesn't matter whether it's in a container or not, it
only matters whether you have a parser/reader for it. There
is no stock DirectShow parser to read raw H.264 files and no
third-party one I can think of. Also, whether IMediaSeeking
would work with such a raw file is implementation-dependent.
Last, most H.264-related filters use MPEG2Video or
VideoInfo2 and neither works with MediaDet, so you would
have to build the graph yourself."
Any body please help me to do this in c#.net?
You'll need to either find or make an MP4 file source filter to make this work. You can build one with mp4v2 or follow the instructions here.
Related
Can any one help me with the code to download all files of particular extension (say *.prt or *.asm) from windchill to local. Please suggest suitable API
It's not really the way Windchill works... Windchill is a PDM software, so you should first search for the correct metadata (certainly EPMDocument in your case), and then get the attach files. You'll have to specify the type of attachment you want to have (primary, secondary content, etc.)
=> you need to understand the datamodel and specify what you really want to do.
You can do a query using queryspec and sort. The download part Im not sure about, but it is possible.
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 use android platform . I have file in InputStream Datatybe , I want to convert it to MediaPlayer and play it
I have two suggestions for you:
Get the entire input into a properly formatted file, and pass that file to MediaPlayer. You're going to have to figure out if your data is formatted properly and how to format it.
Instead of using MediaPlayer, use MediaCodec (http://developer.android.com/reference/android/media/MediaCodec.html) where instead of passing a file or a link you're passing the data itself. With this solution, you're going to have to figure out if you're passing the data properly to Media Codec, but I suspect this is the solution you're looking for. The google documentation does have an example to get you started a bit.
Good luck to you!
What is the format of the data? MP4?
If it is a standard container like MP4 and is a file accessible as a URI in local filesystem (file://) or network (http://) then you should use Google's ExoPlayer library, with demo code here.
I would only resort to using MediaCodec if you have a custom container or transport mechanism.
I'm using KDE, and I'm toying with the idea of hacking the code for Dolphin File Manager (and potentially Konqueror if necessary) to get context-sensitive drag and drop behaviour (i.e. files are moved within the same partition, or copied if they're moved across partitions or the source is read only).
To do this, I think I'd need to find out the containing partition of the source and destination (easy enough on Windows using the drive letter, but on Linux, as mount points can be almost anywhere, it can't be reliably derived from the file path), and compare them.
Does anyone know how I can find out the partition that contains a given file?
It must be possible - I know Nautilus provides this sort of behaviour, but I'm not familiar enough with GTK to track down the appropriate section in the source code to see how its done...
Qt doesn't provide API for this. For POSIX, have a look at stat.
For KDE, you can use KIO::stat() to get mostly the same info as POSIX' stat function but asynchronously.
The device id should be in the field UDS_DEVICE_ID of the result.
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