Got an hour-long video and not really into manually creating subtitles? not plans to put it on YouTube for their automated transcription services? then - try Google Cloud Speech-to-Text! In this post I'll share some scripts for automating the process and creating an
Continue reading "Transcribing Videos with Google Cloud Speech-to-Text"
.str file to go along your video for displaying the subtitles.
So, I've been trying to stream audio off of a USB microphone connected to an Arduino Yun.
Looking into it online I found some examples using ffserver & ffmpeg, which sounded like they could do the trick.
However right from the start I've had many problems with playing the streams on Android and iOS devices.
Seems Android likes a certain list of codecs (http://developer.android.com/guide/appendix/media-formats.html) and iOS like a different set of codecs (Link here), but they do have on codec in common - good ol' MP3.
Unfortunately, the OpenWRT on the Arduino Yun has an ffmpeg build which does not provide MP3 encoding... it does have the MP3 muxer/container format, but streaming anything other then MP3 in it (for example MP2, which the Yun-ffmpeg does have) simply doesn't work on the Android/iOS.
From experiments streaming from my PC a ffmpeg/libmp3lame MP3 stream, it looks like the mobile devices are quite happy with it - so I will need to recompile ffmpeg with Lame MP3 support to be able to stream it.
Continue reading "FFMpeg with Lame MP3 and streaming for the Arduino Yun"
I haven't found a CMake module to find FFMPEG libraries, so I wrote one (a while back) and I thought to share it.
It will look very hard in order to find it on *nix and Win all the same, and I found it useful.
Get the gist: https://gist.github.com/royshil/6318407
So animated gifs are awesome if you're writing a software blog. It saves all this time working with YouTube embeddings and stuff, and your "videos" are stored locally. The simplified FFMPEG writer was before unable to output animated GIFs, but I've tweaked it and now it does. It's also a nice piece of code to learn how to FFMPEG in C.
Continue reading "FFMPEG video writer - now with animated GIF support [w/ code]"
I'd like to share a quick tip on rotating video files.
I'm always frustrated with taking videos with my phone. Single handedly it's easiest to do it when the phone is upright and not in landscape mode. But the files are always saved in landscape mode, which makes them rotated when you watch.
Although there are plenty of GUI software to do it, using the command line is faster and can also be batched!
Continue reading "How to rotate a video using MEncoder and FFmpeg and live to tell the tale"
I recently had to build a demo client that shows short video messages for Ubuntu environment.
After checking out GTK+ I decided to go with the more natively OOP Qt toolbox (GTKmm didn't look right to me), and I think i made the right choice.
So anyway, I have my video files encoded in some unknown format and I need my program to show them in a some widget. I went around looking for an exiting example, but i couldn't find anything concrete, except for a good tip here that led me here for an example of using ffmpeg's libavformat and libavcodec, but no end-to-end example including the Qt code.
The ffmpeg example was simple enough to just copy-paste into my project, but the whole painting over the widget's canvas was not covered. Turns out painting video is not as simple as overriding paintEvent()...
Firstly, you need a separate thread for grabbing frames from the video file, because you won't let the GUI event thread do that.
That makes sense, but when the frame-grabbing thread (I called VideoThread) actually grabbed a frame and inserted it somewhere in the memory, I needed to tell the GUI thread to take that buffered pixels and paint them over the widget's canvas.
This is the moment where I praise Qt's excellent Signals/Slots mechanism. So I'll have my VideoThread emit a signal notifying some external entity that a new frame is in the buffer.
Here's a little code:
Continue reading "Showing video with Qt toolbox and ffmpeg libraries"