WAVDest Filter Specification

The WAVDest (WAVE Destination) filter is used in an output graph, immediately before a FileWriter or DPE Writer filter. It formats the output stream as a WAVE/BWF file.

JSON Structure

JSON

{
    "name": "WAVDest",
    "title": "...",
    "originator": "...",
    "originatorRef": {
        "countryCode": "xx",
        "organizationCode": "xxx",
        "serialNumber": "..."
    },
    "writeRF64": true/false,
    "writeLevlChunk": true/false,
    "writeAuxFile": true/false,
    "channelConfiguration": "...",
    "overlapOnSwitch": ...
    "createMpeg": {
        "bitRate": "...",
        "jointStereo": "..."
    }
}

Field	Description
title	This string is written to the Description field of the BWF file's metadata. The field is optional, default is an empty string. The usage of placeholders is supported for this field (e.g. `"title": "Recording ${StartTime\|HH:mm:ss.fff}"`). Note: If the title is empty, no BWF metadata header (i.e., a “bext” chunk in the WAV file) will be created, and the fields “originator” and “originatorRef” are ignored!
originator	This string is written to the Originator field of the BWF file’s metadata. The field is optional, default value is `"ROAD"` .
originatorRef	This optional object can defined to set the non-automatic parts of the OriginatorReference field of the BWF file’s metadata. countryCode: ISO 3166-1 2-letter code of the country of origin. The field is optional, default is the country code of the host computer's system locale. organizationCode: 3-letter code of the organization, which created the file. The field is optional, default is `"NNN"`. serialNumber: Up to 12 alpha-numeric characters to designate the device, which made the recording. The field is optional, default is the host computer name.
writeRF64	Either `true` or `false`. If `true`, the target file is written in a way, that the format will switch to RF64 on the fly, as soon as the file size exceeds 4GB. The field is optional, default is `true`.
writeLevlChunk	Either `true` or `false`. If `true`, BWF metadata containing the waveform is written to the file. The field is optional, default is `true`. See “LvlChunk and Aux files” section below.
writeAuxFile	Either `true` or `false`. If `true` and writeLvlChunk is also `true`, an AUX waveform file is created while the recording is in progress and deleted when the recording has finished. The field is optional, default is the ROAD Service’s parameter WorkerWriteAuxFile. See “LvlChunk and Aux files” section below.
channelConfiguration	This field is optional. If present, the WAVE file header will be formatted as a "WAVE Extended" header with a "channel mask" field indicating the file's channel configuration. Supported values are: `"Mono"`, `"Stereo"`, `"5.0"`, `"5.1"`, `"7.1"`, `"5.0+Stereo"`, `"5.1+Stereo"`, `"7.1+Stereo"`. If the number of audio channels in the graph doesn't match the number of channels needed for the given configuration (e.g. 8 channels for `"5.1+Stereo"`), the job will abort with an error.
overlapOnSwitch	A time in milliseconds, which specifies an "overlap" in the audio between two adjacent database entries in case of output switches. The field is optional, default is 0 (i.e. no overlap).
createMpeg	This object is optional. If it is present, the audio content of the WAVE file will be encoded as MPEG Layer 2. bitRate: Bit rate in kbit/s. Valid values are 192, 160, 128, 112, 96, 80, 64, 56, 48, 32 for mono, and 384, 320, 256, 224, 192, 160, 128, 112, 96, 64 for stereo. The field is optional, default is 192. jointStereo: Either `true` or `false`. If `true`, and you have a stereo encoding, the encoder will use "Joint Stereo" mode. The field is optional, default is `false`.

Notes:

MPEG encoding is only possible, if the output graph has not more than 2 channels, and its sample rate is valid for MPEG Layer 2 (32000, 44100 or 48000).

LvlChunk and Aux files

The lvlChunk for waveform data is written only after the recording has finished (and only if the parameter writeLevlChunk is not set to false). Opening a multi-hour recording in MTE (BWF[MP2]) while the file is still being created can therefore take a significant amount of time if the waveform data is not there. For this case the writeAuxFile parameter can be set to control creation of an AUX waveform file during recording. This enables MTE to open it without this delay.

After a recording was completed and the lvlChunk was written to the audio file, the AUX file is deleted.

Aux files only support 1 or 2 channels recordings.
Aux file creation require that the downstream filter is the DPE Writer filter.
The aux file creation is only supported when direct file access is used. See DPE Writer Filter Specification directFileAccess.

If this parameter is not set, it will default to the general setting WorkerWriteAuxFile in the ROAD Service’s config file (see Configuration Parameters of ROAD Service).