I have a series of about 600 JPEG images with sequential filenames. what I need is to create an AVI video. cvCreateVideoWriter didn't return NULL! Initially frames got started to form video but after few frames program terminates... i don't know what i am going wrong.
can anyone help? i would really appreciate that. Thanks in advance.
OpenCV uses VFW and only creates standard AVI files which are limited to 2Gb
You can use ffmpeg to create either mp4 or extended openDML type AVIs
The easiest solution is normally to pipe image frames to something like memcoder rather than having to deal with the details of the video library yourself - see http://opencv.willowgarage.com/wiki/VideoCodecs
Related
I have a .swf file, which i want to embed in my opencv and overlay over camera stream and display it to the user. Until now i have not found a solution by simple google search. I would appreciate if anyone has any idea how to approach this.
Thanks
OpenCV doesn't deal with .swf files, so you need to use some other technology like FFMPEG or GStreamer to retrieve the frames and decode them to BGR to be able to create a valid IplImage (or cv::Mat if you are insterested in the C++ interface).
GStreamer also provides a simple mechanism to stream video over the network.
I need some ideas about how to stream video feed coming from opencv to a webpage. I currently have gStreamer, but I don't know if this is the right tool for the job. Any advice on using gStreamer or any hyperlinks to tutorials would be helpful and appreciated!
Thanks!
OpenCV doesn't provide an interface for streaming video, which means that you'll need to use some other techonology for this purpose.
I've used GStreamer in several professional projects: this is the droid you are looking for.
I do not have any experience w/ streaming OpenCV output to a website. However I'm sure this is possible using gstreamer.
Using a gstreamer stream, it is possible to get data and convert the data in to OpenCV format. I recommend you read up on GstAppSink and GstBuffer.
Basically, if I remember correctly, you must run a pipeline in the a background thread. Then using some function in gst_app_sink, you can get the buffer data from the sink.
A quick lookup on the issue, you had to use GST_BUFFER_DATA for this
I remember having to convert the result from yCBCr to bgr, a collegue had problems as the conversion of opencv was inadequate. So you might have to write your own. (This was back in the IplImage* days)
What I'm trying to do is exactly as the title says, decode multiple compressed audio streams/files - it will be extracted from a modified MP4 file - and do EQ on them in realtime simultaneously.
I have read through most of Apple's docs.
I have tried AudioQueues, but I won't be able to do equalization, as once the compressed audio goes in, it doesn't come out ... so I can't manipulate it.
Audio Units don't seem to have any components to handle decompression of AAC and MP3 - if I'm right it's converter only handles converting from one LPCM format to another.
I have been trying to work out a solution on and off for about a month and a half now.
I'm now thinking, use a 3rd party decoder (god help me; I haven't a clue how to use those, the source code is greek; oh and any recommendations? :x), then feed the decoded-to LPCM into AudioQueues doing EQ at the callback.
Maybe I'm missing something here. Suggestions? :(
I'm still trying to figure out Core Audio for my own needs, but from what I can understand, you want to use Extended Audio File Services which handles reading and compression for you, producing PCM data you can then hand off to a buffer. The MixerHost sample project provides an example of using ExtAudioFileOpenURL to do this.
User can upload any video of any type... after that I need to convert this video to *.flv
How can I do this using RoR?
We do this with paperclip and ffmpeg. Paperclip allows you to add custom processors to a Paperclip attachment. We created such a processor which just calls ffmpeg on the command line to create the flash version of the video. ffmpeg even allows you to extract stills from the video for thumbnail representations.
With paperclip and ffmpeg and flvtool2
Have look at this gist with all you'll need. https://gist.github.com/507804
It has:
Video to thumbnails
Video to flash
Correct geometry calculations etc...
There are two ways to do it, yourself or hosted solution.
If you want to do it yourself, start with Bert's solution and go from there. Remember transcoding is CPU intensive, so you likely need to have a another server/on-demand instance doing this
If you want to go for a hosted solution, see Kaltura.com or encoding.com
sign up for pandastream - available as a heroku add-on as is zencoder
they're not cheap options though so maybe look around for something less costly first
Everyone knows about there instructional videos http://delphi.wikia.com/wiki/Delphi_Videos but I want to watch them on my iPad when I go on vacation.
The problem is the videos are in swf and will not play on my iPad. Does any know of another source for these videos in another format?
Thanks.
For the moment flash video is the container of choice for most video content on the internet. Saif is right. If you want those specific videos you'll need to convert them yourself. There are several decent flv to mp4 converters available for free (Miro comes to mind). SWF is takes a bit more work to extract the video content.
Now if you are looking for Delphi content that's already available in MPEG 4 you can try http://edn.embarcadero.com/tv. The content from the most recent Coderage event is available as an mp4 download.
You can convert them into a proper format using a free video convert like Any Video Converter
I've had reasonable success watching on-line Flash content on my iPad using iOSFlashVideo.
Not tried it on off-line flash files though.
--jeroen