Rec/Playback

 

 

 


 

Recording & Playback

The software supports recording of:

  • Audio (WAV, MP3, WMA), and
  • IQ (RAW) data,

in addition full support for IQ playback.

 

Audio

The software supports recording of audio in

  • WAV (Waveform Audio File Format, lossless),
  • MP3 (MPEG-1 or MPEG-2 Audio Layer III) and
  • WMA (Windows Media Audio).

Note: to record audio you must have at least one receiver started.

A comparison of a 60 second recording, amateur radio, single sideband.

WAV: 5,800 KB
MP3:   464 KB
WMA:   492 KB

Comparing the audio quality of these recordings, WMA is better although the output file is approximately 5% larger. General opinion is that WMA is better tham MP3 as lower bit rates.

From the Rec/Playback pane in the ribbon bar select Audio Record, the Record Active Receiver window is displayed.

  • Title - used as the filename,
  • Folder - where the file is stored,
  • Format - either MP3, WAV (lossless) or WMA,
  • Length - if not checked then the length is unlimited,
  • Other - optionally do not record when the output is squelched - usually FM transmissions.

Press Start to enable the recording. When a recording is active a Yellow speaker icon and the Recording test is displayed in the receiver window.

Browse

Pressing the Browse button in the Rec/Playback pane displays a list of folders where audio has been stored by this software. Selecting an entry from the list opens the Windows file explorer in the selected folder.

Playback

Playback is not supported as there are many options already available for the Windows platform.

 


Data (IQ) Recording

From the Rec/Playback pane in the ribbon bar select Data :: Record, Record, the Start Recording window is displayed.

The options include:

  • Scheduling the recording,
  • Size of each file,
  • Sample size (16-bit is recommrnded),
  • Lock the radio so it is not accidently changed while a recording is in progress.

Press Start to start the recording. While a recording is in progress the status is displayed in the waterfall.

File Format

(Version 3.0.7) WAV and WAV RF64 formats are supported. WAV only supports files up to 2GB in size whereas WAV RF64 supports an unlimted file size (actually approximately 16 exabytes).

If the file size is not selected or is seleacted with a value greater than 2GB then WAV RF64 is used, otherwise WAV is used.

Storage

The device where the data is stored must support the data rate as shown above for more than just a few seconds - some cheaper SD cards do not support a sustained data tranfer rate.

  • If possible dedicate a device to IQ recordings,
  • Make sure the selected device is only used for recording and is not used by other processes,
  • Disable Windows indexing and/or defragmentation,
  • If usinag an external USB drive it must have enough USB power.

USB Sticks, SD Cards

Despite claims by manufacturers, these devices do not necessarilly support the systained throughput rate required for data recording. If the console freezes while recording this will often be due to the output device. If in doubt record to a hard drive, for best writing speeds use SSD.

FAT32 / NTFS

Devices such as USB sticks and SD cards formatted with the FAT32 file system generally don't support the sustained throughput rates required for data recording. Only NTFS devices are supported, if you want to use a FAT32 device you must first record to a NTFS device, then copy the files to the FAT32 device.

 


Responsive-V

Data (IQ) Scheduler

The data scheduler is a powerful recording feature described in detail here.

 

Responsive-S

 

Data (IQ) File Format

Formats

WAV

Most SDR programs save IQ recordings using the WAV file format. The disadvantage of this format is a maximum file size of 2GB on Windows, so long recordings required:

  • Many smaller (<= 2GB) files,
  • Logic to playback this files as a single recording.

Since the start of SDR software bandwidths have grown significantly for 192kHz of the SDR-IQ to 10 MHz with the Airspy R2 or 50 MHz with the Lime SDRs, so an alternate format is desirable. Fortunately this already, exists - WAV RF64.

WAV RF64

This format is based on WAV with a maximum filesize of approximately 16 exabytes (1 million terabytes). SDR Console supports recording and playback with the WAV RF64 format, however some popular IQ analysis/playback programs do not support this format. If a program cannot play back a WAV RF64 then you must create the recording using the WAV format. A typical error message when WAV RF64 is not supported is 'Invalid RIFF Headrer'.

Selecting

Data (IQ) Recording

When you start a Data (IQ) Recording the file format is shown when you select the individual file size.

Scheduler Definition

When you create a Scheduler Definition look at the Single file (WAV RF64 format) option.

 


 

Data (IQ) Playback

From the Rec/Playback pane in the ribbon bar select Data :: RecordOpen, the Select Recording window is displayed.

Select a recording, then press Play. To aid navigation of the selected recording select Navigator from the Rec/Playback pane in the ribbon bar.