Hi I have an adobe air 2 project which records some short sounds via the microphone. I am able to save the streams as wav files but require them to be saved as mp3 (For replaying in the flash player).
Does anyone know if this is possible?
If it isn't is there anyway to get the flash player to player audio in wav form?
Any hints appreciated.
If you are using Adobe AIR v2 then you should be looking for a Non-AS3 commandline tool to convert the wav file to mp3. The process is fairly CPU intensive and would take a LONG time in Actionscript even if there was a library out there that accomplished the task (which I haven't heard of).
My suggestion is to include a tool like LAME with you application and pass your wave file to it (essentially running the process in another thread in C). The only downside is providing an executable for each potential OS you'll be deploying to, if you intend on support Windows, Mac, and Linux that could be up to three different Wave->Mp3 commandline tools.
Link for LAME: http://lame.sourceforge.net/
Seems to be possible: http://www.jordansthings.com/blog/?p=5. No ready source, but libraries listed there should help. (I would just decompile it if need be.)
Related
I have a music playlist folder in my Flash drive (pen drive), music names are sorted in a fixed manner, I want to shuffle my music playlist by renaming the files. Generally I use Flash drive to play music in my car.
Is it practically possible to write a program for a flash drive? On inserting a flash drive into PC/car firmware; music files in the playlist folder must be shuffled every time.
Thank you.
I searched on web, I didn't find useful resources to accomplish the task.
It's only possible if either of the following are true:
The "computer" you're inserting it into supports running code. (Like an autoexec.bat on Windows). Obviously this depends entirely on what CPU/"OS" your car's audio player runs. Unlikely that there's any intentional support for executing code, but you might find an exploit that would let you run code on your car's audio-player microcontroller. The audio player probably doesn't really have an OS, it's probably just a lightweight custom system.
Your flash drive can run custom firmware that has a driver for FAT32 and modifies its own contents on powerup, before making itself visible to the host.
Flash drives do have a microcontroller internally to run the flash remapping / wear-leveling firmware. But usually there's no documented interface for uploading programs to it. And normally it doesn't know anything about filesystems, only block-level stuff, so anything you wanted to stuff into it would have to include a driver for FAT32.
I assume some people have reverse-engineered the programming / firmware-update interface on some flash drives.
You can probably also get USB devices that are designed to run custom programs like this as well as act as USB storage. If you really really want this (and your car doesn't have a "randomize" mode you can use instead), buying a USB-storage device that was designed to be programmable would probably be the easiest way to go. I assume such things exist but IDK.
Do you know any application that will display me all the headers/parameters of a single H264 frame? I don't need to decode it, I just want to see how it is built up.
Three ways come to my mind (if you are looking for something free, otherwise google "h264 analysis" for paid options):
Download the h.264 parser from (from this thread # doom9 forums)
Download the h.264 reference software
libh264bitstream provides h.264 bitstream reading/writing
This should get you started. By the way, the h.264 bitstream is described in Annex. B. in the ITU specs.
I've created a Web version - https://mradionov.github.io/h264-bitstream-viewer/
Based on h264bitstream and inspired by H264Naked. Done by compiling h264bitstream into WebAssembly and building a simple UI on top of it. Output information for NAL units is taken from H264Naked at the moment. Also supports files of any size, just will take some time initially to load the file, but navigation throughout the stream should be seamless.
I had the same question. I tried h264 analysis, but it only supports windows. So I made a similar tool with Qt to support different platforms.Download H264Naked. This tool is essentially a wrapper around libh264bitstream
New to Mac OS X, familiar with Windows. Windows has DirectShow, a good number of built-in filters, COM programming, and GraphEdit for very fast prototyping and snooping on the graphs you've constructed in code.
I'm now about to go to the Mac to work with cameras, webcams, microphones, color spaces, files, splitting, synchronization, rendering, file reading, file saving, and many of things I've come to take for granted with DirecShow when putting together applications for live performance. On the Mac side, so far I've found ... nothing! Either I don't know where to look or I'm having the toughest time tying the Mac's reputation for its ease of handling media with a coherent programmatic ability to get in there and start messin' with media manipulatin' building blocks.
I've seen some weak suggestions to use gstreamer or some library for QT but I can't bring myself to believe that this is the Apple way to go. And I've come across some QuickTime documentation but I'm not looking to do transitions, sprites, broadcasting, ...
Having a brain trained on DirectShow means I don't even know how Apple thinks about providing DirectShow-like functionality. That means I don't know the right keywords and don't even know where to look. Books? Bought a few. Now I might be able to write some code that can edit your sister's wedding video (if I can't make decent headway on this topic I may next be asking what that'd be worth to you), but for identifying what filters are available and how to string them together ... nothing. Suggestions?
Video handling is going through a huge transition on the Mac at the moment. QuickTime is very old, but also big and powerful, so it's been undergoing an incremental replacement process for the past 5 years or so.
That said, QTKit is the QuickTime subset (capture, playback, format conversion and basic video editing) which is supported going forward. The legacy QuickTime APIs are still there for the moment, and probably will remain at least until its major features are available elsewhere, but are 32-bit only. For some involved video stuff you may end up needing to use it in places.
At the moment, iOS is ahead of the Mac because it could start from scratch with AV Foundation. The future of the Mac media frameworks will probably either be AV Foundation directly (with QTKit being a lightweight shim over the top) or an extension of QTKit that looks very similar.
For audio there's Core Audio which is on Mac and iOS and isn't going away any time soon. It's quite powerful but somewhat obtuse in places. Luckily online support is very good; the mailing list is an essential resource.
For filters and frame-level processing you've got Core Video as someone else mentioned, as well as Core Image. For motion graphics there's Quartz Composer which includes a graphical editor and a plugin architecture to add your own patches. For programmatic procedural animation and easily mixing rendering models (OpenGL, Quartz, video, etc.) there's Core Animation.
In addition to all of these, of course there's no reason you can't use open source libraries where the built-in stuff doesn't do what you want.
To address your comment below:
In QuickTime (and QTKit), individual data types like audio and video are represented as tracks. It may not be immediately clear that QuickTime can open audio as well as video file formats. A common way to combine audio and video would be:
Create a QTMovie with your video file.
Create a QTMovie with your audio file.
Take the QTTrack object representing the audio and add it to the QTMovie with the video in it.
Flatten the movie, so it doesn't simply contain a reference to the other movie but actually contains the audio data.
Write the movie to disk.
Here's an example from Blender. You'll see how the A/V muxing is done in the end_qt function. There's also some use of Core Audio in there (AudioConverter*). (There's some classic QuickTime export code in quicktime_export.c but it doesn't seem to do audio.)
I have to make a hardware project using a microcontroller, memory, screens, etc.
Is it possible to make an independent PDF / documents reader, which is capable of running on battery power?
Please note I don't want to use any technology which needs licensing. It must be all freeware readers, etc., and programing language can be assembly, C, Flash or any.
I have submitted proposal of PDF reader project (independent hardware). Many say it's impossible. What should I do?
Reading and displaying a PDF document is quite a "high level operation".
You should start with a microcontroller starter kit, with an ARM9 processor or something similar. Then install a Linux operating system on it, include a standard display driver and run an X server. Then you should be able to find a Linux based PDF reader with X drivers.
To 2nd another comment here, I would say that you're not going to to do this with a microcontroller, you're going to need to get some more powerful ARM CPU like an ARM9, Cortex-A8 or similar with a decent amount of RAM.
You'll probably need something that's capable of running Linux if you want to start with pieces of software that won't require writing quite a large volume of software from scratch.
Note that for commercial devices that are out there, including the Kindle, run Linux, and aren't based on a micrcontroller.
You might be best off getting something like a BeagleBoard, attach a display to that, and start from there with an X-based PDF viewer.
I'm looking into writing an app that runs as a background process and detects when an app (say, Safari) is playing audio. I can use NSWorkspace to get the process ID's of the currently running applications but I'm at a loss when it comes to detecting what those processes are doing. I assume that there is a way to listen in on a process and detect what public messages the objects are sending. I apologize for my ignorance on the subject.
Has anyone attempted anything like this or are aware of any resources that can help?
I don't think that your "answer" is an answer at all...
and there IS an answer (which is not "42")
your best bet for doing this would be to write a pass-through audio output device. Much like soundflower, actually. so your audio output device would then load the actual (physical) audio output device and pass the audio data along to it directly (after first having a look at the audio stream, of course!). then you only need to convince your users to configure your audio device as the default audio output device so that the majority of applications which play sound will use it automatically. and voila...
your audio processing function will probably just do a quick RMS on the buffer before passing it along to the actual output device. and when the audio power crosses a certain threshold (probably something like -54dB with apple audio hardware), then you know that some app is making sound.
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SoundFlower is an open-source project that allows Mac OS X applications to pass audio to each other. It almost certainly does something similar to what you describe.
I've been informed on another thread that while this is possible, it is an extremely advanced technique and not recommended. It would involve using Application Enhancer (APE) and is considered a not 'nice' thing to do. Looks like that app idea is destined for the big recycling bin in the sky :)