iBroadcast Audio Guide

The guide is here to detail the ins and outs of the iBroadcast system for audiophiles and those who want to know exactly how the system is designed and to get the most out of their iBroadcast experience. This guide is somewhat technical and not meant for casual users, but for those that want to know what is going on under the hood.

Uploading, Storage & Transcoding

The first step in getting started with iBroadcast is uploading your music library. You can do this with our MediaSync Lite app, or using the website. When you upload a file to the system it first transcodes the file to mp3 format at a bit rate of 128kbps and a sample rate of 44.1Khz using the mp3lame audio codec.

We do this for several reasons:

  1. It confirms the file is indeed a valid audio file, if the transcoding fails for any reason, the file is rejected.
  2. It is then converted to a format, bitrate and sample rate that will play on virutally any device
  3. That resulting file is then used when streaming with the free, core service

At this point, your original file is also stored byte-for-byte as you uploaded, and kept safely in our datacenter. You can download this file at any time to retrieve it. The resulting transcoded file is used when streaming at 128kbps using the iBroadcast app or website. For many users, this format and quality is acceptable.

1) Upload your audio files into your iBroadcast library using MediaSync Lite or the web browser. 2) Files are then transcoded, validated and stored on the iBroadcast servers where you can retrieve them byte-for-byte the same file anytime. 3) Track is then made available in your iBroadacst library for streaming.

High Defination Streaming

Some users however, especially those with high end equipment, may want to stream their library in higher bitrates and different audio formats to maximize their listening experience. iBroadcast provides this with our Premium Service.

When you choose to stream in "original" uploaded format, your files are streamed from our datacenter to your device using the exact, byte-for-byte file you originally uploaded. However, there are some caveats to this and we outline those below.

Audio Codecs & Device Support

When you choose to stream your files in the "original" format, you are responsible for making sure the device you are streaming to suppports that format.

Bitrate is often refered to as the audio quality of a file. It is the "amount" of data the file has. Common bitrates which we provide with the Premium Service are 96, 128, 192, 256, and 320kbps.

We also provide the option to stream in "lossless compression", this is where the term "bitrate" does not apply and the term "bit depth" comes in to play. More on that later.

The audio codec and the sample rate is where you can potentionally run into compatibility issues with audio devices (speakers, DACs, and even Google or Echo smart speakers). The codec and sample rate must all be supported by that device, or your file may play poorly or simply fail to play at all.

This is one reason why we provide other transcoded bitrate options. These transcoded mp3 files are encoded in such a way to be highly compatible. If your original file fails to play, you can use a transcoded bitrate which is almost guaranteed to play across all devices.

Transcoded Streaming

We offer the ability to play at several transcoded bitrates for premium users. This option is useful if your original files are not supported on the device you are streaming to, you are on a metered internet connection, or if you are on a slow internet connection and do not already have your audio files cached to your device.

In this situation your files are "live" transcoded on the iBroadcast servers as you stream or cache them to your device. We offer 96, 192, 256, and 320kbps additional bitrates for premium users. These are transcoded from the original file you uploaded, converted to mp3 using the mp3lame codec, resampled to 44.1khz and at the requested bitrate.

Note: If the original file you uploaded is 256kbps and you request 320kbps, the file is not "upscaled" and instead streamed at 256kbps

1) File is requested from iBroadcast servers, which live transcode your file at the requested bitrate. 2) App streams or downloads your file. 3) File is played to your selected output device.

Sample Rate & Bit Depth

When an output device (i.e. your phone) receives digital audio data from the iBroadcast app it converts that back into an analog waveform to produce sound mechanically though a speaker. The more digital data-points in a file, or samples per second, the more "high definition" the playback and the more closely it will sound to the original analog source. This "sample rate" is the amount of data per second sampled from the original, analog sound.

Each sample also has an amount of data it can represent. That amount is called the "bit depth". The higher the bit depth and the more often the sample rate, the higher quality the analog conversion will be. For reference, a typcal CD has a 16 bit depth, and a 44.1khz sample rate. If you "rip" a CD to a flac file, this 16bit/44.1khz is maintained and is considered "lossless format" and the most widely used.

The graph below shows how sample rate and bit depth are related. There are many more, very in-depth guides available on the internet if you wish to know more about this topic.

Increasing sample rate and bit depth increases the audio resolution and allows more accurate conversion from an analog waveform. In this diagram the red wave is the analog sound and the blue is the digital representation of that.

Resampling

The iBroadcast apps will query your output device and ask it for its sample rate setting. Attempting to play audio at a sample rate other than what the device is configured for often produces undesired results such as "popping" or other audible artifacts. If a file's sample rate is higher or lower than what is supported by a device then audio data must be resampled by the app before it is sent to the device. This is can be a very cpu intensive operation. On some older phones, or a phone running many apps at the same time, can also cause "studdering", "popping", or playback stopping all together.

However, if the file you are streaming has the same sample rate as the device you are outputting to, the file will not be resampled. This will give you the highest possible quality playback.

The app will query the output device to determine the sample rate. This is often set by the manufacturer but some DACs and other high end devices allow this to be set by the user.
The app resamples the playing track to match the sample rate of the output device. In this example, the source file's sample rate is 44.1khz, so the app will resample that during playback to match the device's at 96khz.

Additional Help

We hope that answers all the questions you have about how the iBroadcast system works. If you have any additional questions or concerns please reach out to us! We are here to help you in any way we can!