DVR Capability for Radio?!

Extide · 04-10-2009, 12:50 PM

So, I am working on a C# app to allow DVR capability to radio (or just about any line-audio source). Anyone else out there done anything similar? I am fairly close to getting it to work.

Buffer in memory or on disk? (Maybe configurable?) -- For now I will do in memory as it will be a lot easier, but I will have to watch memory usage.

I am working mainly to target the SiLabs tuner as that's what I have...

The "front end" I am working on is more of a POC for a few things.
-.net 3.5 on carpc
-sqlce on carpc
-LinQ to SQLCE and LinQ to objects
-Designed for function over form at this point

Music database with realtime search and dynamic playlist capabilities.
Hopefully eventually add support to subclass iGuidance screen to have GPS map in app.
I have not yet decided how I will play media. I am thinking of including support to natively decode most audio files (mp3, wma, flac, ogg are my main interests).
Maybe more stuff....

VERY EARLY ALPHA screenshot of music browser control:

strikeback03 · 04-10-2009, 01:01 PM

http://cgi.ebay.com/Visteon-Zoom-HDZ...QQcmdZViewItem

that software claims to be able to do it for HD radio. I'd love to be able to hit a button listening to XM or whatever to save a copy of the transmission.

Extide · 04-10-2009, 01:35 PM

So far I have enough code to record to disk, and then also playback the file from disk. Now I just need to make it so I can navigate through the file at will (dvr style). I wonder how I will be able to deal with trimming the front side off as the file will get pretty big over time (it is basically un-compresed wav data).

I think I might also use the bass.net audio library, it looks like it supports just about everything I need.

This isn't going to be as hard as I thought it might be!

Anyways I will keep posting updates as they come. (I am not really interested in existing solutions unless they are in C# and open source as I want to make this, part for fun, part to be able to make it do exactly what I want.)

-James

malcom2073 · 04-10-2009, 01:36 PM

This is fairly awesome, I'll keep an eye on this

GizmoQ · 04-10-2009, 03:27 PM

Quote: Originally Posted by Extide

So, I am working on a C# app to allow DVR capability to radio (or just about any line-audio source). Anyone else out there done anything similar? I am fairly close to getting it to work.

A few years ago, I wanted the same type recorder capability. Since I run Ride Runner, I decided I wanted a command line interface that could record from several different sources (FM, XM, Internet radio, YouTube, etc.) and save an MP3 using the title/artist from RDS or internet stream title with one click. Took me about 6 months to find and another 2 to program my buttons, but I settled on a commercial app called Loop Recorder (expensive as hell, but does everything I want and more).

Extide · 04-10-2009, 04:11 PM

Cool. I have it basically working now, will need to test with some different audio sources to make sure.

Record stream goes back to position 0 at end of buffer
Play stream also loops back to start at the end, follows the record position.
Playback seek fwd & back works.

Currently I am looking around at free and preferably open source audio libraries for decoding mp3, flac, wma, ogg, etc. I have found a few but I am not completely happy yet.

Oh, this is also going to be fully opensource and free. I have an SVN server where my code is at. I just need to setup a public read only account for everyone. If people want to contribute I will give out account with write access. Give me a little bit to set things up and whatnot.

rtgree01 · 04-11-2009, 09:09 AM

I have wanted something similar. Everything you've mentioned sounds great.... but there are times when I want to pause or rewind the live audio feed....
As an example.... I'm spaced out on my drive to work... the radio starts playing the traffic report... I'm barely paying attention until I hear a particular street, but missed that there was an accident on it.... if I could rewind 15 seconds and hear what it was, that would be nice...
It looks like you were most concerned about recording songs and labeling them with their information... and that is great. But I would love to have the "Pause Live Audio" capability....

I am a developer, so I could be interested in helping out where I can....

Ryan

barnyard · 04-11-2009, 10:32 PM

What he said...

Extide · 04-13-2009, 12:53 PM

Yeah. sorry the screen shots only show the music interface -- the radio screen is only a few buttons right now, but you will have pause, rewind, etc capability for live radio. I am going to allow you to specify an on-disk buffer size (of like 100MB or whatever) that it will record the audio into FIFO style, and just loop back to the beginning of the file after recording to the end, then you can playback from any point in the file (directly following the record stream or whatever). 100mb should get about 10 mins, the audio data is essentially raw uncompressed PCM data, so 16bit * 44.1khz = 705600 bits a second, which is ~86KB a sec. (Can't remember if that accounts for stereo or just one channel) I was ill all this past weekend so I didn't get to work on it, but will spend some more time this week. Anyways it will be easy to use, just like a DVR for TV. I am only really designing it for the SiLabs FM Tuner (because that's what I have) but since it really is like a wav in / wav out record / play system it could theoretically be adapted for almost anything...

barnyard · 04-13-2009, 02:59 PM

Awesome! Looking forward this

Extide · 05-12-2009, 07:03 PM

Worked on this a bit today .. the app is kind of a mess at the moment as I decided to change around the way a lot of stuff works and not everything is really updated yet. Not much works in here except the media scanner, playlist browser/creator and the radio record/play currently kind of works. You can't currently record and play at the same time or it will record what itself is playing UNLESS you select something external as your record device, and make sure that that device isnt actually playing thru the speakers. In any case you can kind of get a sneak peek.

Requires Visual Studio 2008
Written in C#
Uses SQLServer Compact Edition, and Windows Media Player SDK

This is more of a development snapshot than anything.. have fun!

BTW This project is going to take me a WHILE to complete, it isnt really forgotten about but I can't really spend much time on it.

User Name		Remember Me?
Password