# Creating audio-only outputs Creating audio-only outputsCreate audio-only outputs in a DASH container MediaConvert added support for audio-only DASH outputsCreate audio-only outputs Learn how to create MediaConvert outputs that contain only audio, without video. You can use AWS Elemental MediaConvert to create outputs that contain only audio, without video. With audio-only outputs, MediaConvert supports a more limited number of codec and container combinations for input and output files. The restrictions and procedures in this chapter apply to outputs that don't have video in the container. This includes the following: + Outputs in **File** output groups that don't have video included + Streaming **HLS** output groups that contain only audio outputs + Streaming **DASH** output groups that contain only audio outputs When you set up streaming output packages that contain audio, video, and captions, you create separate outputs for each element inside the output package. These are not audio-only outputs as described in this chapter. For more information about setting up streaming outputs, see [Creating outputs in ABR streaming output groups](setting-up-a-job.md#create-outputs-in-abr-streaming-output-groups). You set up an audio-only output in the same way that you set up an output that contains video, except that you don't include video or captions. MediaConvert generates the following files for audio-only outputs: + **File** output groups: One separate audio-only file for each output. + **HLS** output groups: A single rendition in the ABR stack for each output. + **DASH ISO** output groups: A single rendition in the ABR stack for each output. **Note** For AAC streaming outputs, the initial segment is longer in duration than the others. This is because, with AAC, the initial segment must contain silent AAC pre-roll samples before the audible part of the segment. MediaConvert accounts for these extra samples in the timestamps, so the audio plays back correctly. **To create an audio-only output (console)** 1. To confirm that MediaConvert supports your input files, consult the input table in [Supported output formats for audio-only workflows](audio-only-output.md). 1. Set up your job as described in [Tutorial: Configuring job settings](setting-up-a-job.md), but with the following differences: + Remove the **Video** tab in the **Encoding settings** section of your output. + Choose a supported output container and audio codec from the output table in [Supported output formats for audio-only workflows](audio-only-output.md). + Include only one group of audio settings per output. That is, don't choose **Add audio** to create an **Audio 2** tab under **Encoding settings**. 1. If your outputs are in an **HLS** output group, choose a container for the audio-only output. Under **Output settings**, in the **Audio** section, for **Container for audio-only output**, choose **MPEG-2 Transport Stream** to create a file in an MPEG2-TS container. Keep the default value **Automatic** to create a raw audio-only file with no container. **To create an audio-only output (API, SDK, and AWS CLI)** 1. To confirm that MediaConvert supports your input files, consult the input table in [Supported output formats for audio-only workflows](audio-only-output.md). 1. Set up your JSON job specification. Either manually edit your JSON file, or use the console to generate it as follows: 1. Follow the previous procedure for the console. 1. In the **Job** pane on the left, under **Job settings**, choose **Show job JSON**. The JSON job specification for audio-only jobs differs from standard jobs as follows: + Exclude each instance of `VideoDescription` and its children from the `Outputs` portion of your job JSON. + For each output, include only one child group of audio settings under `AudioDescriptions`. + For audio-only outputs in an **HLS** output group, specify a container for the audio-only output. Under `Outputs`, `OutputSettings`, `HlsSettings` include the property `HlsAudioOnlyContainer`. Set it to `M2TS` to create a file in an MPEG2-TS container. Set it to `AUTOMATIC` to create a raw audio-only file with no container. `AUTOMATIC` is the default behavior. **Topics** + [ # Supported output formats for audio-only workflows ](audio-only-output.md) + [ # Audio-only job settings limitations ](feature-limitations-for-audio-only.md) # Supported output formats for audio-only workflows Supported output formats MediaConvert supports the following combinations of output container and codec for creating audio-only outputs. Some containers and codecs have additional restrictions. For more information about the audio container or audio codec choose its link in the following reference table. Or see [Supported containers and codecs reference tables](supported-containers-codecs-details.md). | Container | Audio Codecs | | --- | --- | | [DASH (Dynamic Adaptive Streaming over HTTP)](supported-containers-codecs-details.md#container-dash) | [AAC](supported-containers-codecs-details.md#codec-aac) [Dolby Digital (AC3)](supported-containers-codecs-details.md#codec-ac3) [Dolby Digital Plus (EAC3)](supported-containers-codecs-details.md#codec-eac3) [Dolby Digital Plus JOC (Atmos)](dolby-atmos.md) | | [HLS (Apple HTTP Live Streaming)](supported-containers-codecs-details.md#container-hls) | [AAC](supported-containers-codecs-details.md#codec-aac) [Dolby Digital (AC3)](supported-containers-codecs-details.md#codec-ac3) | | [MP4 (MPEG-4)](supported-containers-codecs-details.md#container-mp4) | [AAC](supported-containers-codecs-details.md#codec-aac) [Dolby Digital (AC3)](supported-containers-codecs-details.md#codec-ac3) [Dolby Digital Plus (EAC3)](supported-containers-codecs-details.md#codec-eac3) | | [MPEG-TS (MPEG-2 Transport Stream)](supported-containers-codecs-details.md#container-mpeg-ts) | [AAC](supported-containers-codecs-details.md#codec-aac) [Dolby Digital (AC3)](supported-containers-codecs-details.md#codec-ac3) [Dolby Digital Plus (EAC3)](supported-containers-codecs-details.md#codec-eac3) [MPEG-2](supported-containers-codecs-details.md#codec-mpeg2) | | [OGG](supported-containers-codecs-details.md#container-ogg) | [FLAC](supported-containers-codecs-details.md#codec-flac) [Vorbis](supported-containers-codecs-details.md#codec-opus-vorbis) | | [No container](supported-containers-codecs-details.md#container-none) | [AAC](supported-containers-codecs-details.md#codec-aac) [AIFF](supported-containers-codecs-details.md#codec-aiff) [Dolby Digital (AC3)](supported-containers-codecs-details.md#codec-ac3) [Dolby Digital Plus (EAC3)](supported-containers-codecs-details.md#codec-eac3) [FLAC](supported-containers-codecs-details.md#codec-flac) [MPEG-2](supported-containers-codecs-details.md#codec-mpeg2) [MP3](supported-containers-codecs-details.md#codec-mp3) [WAV](supported-containers-codecs-details.md#codec-pcm) | # Audio-only job settings limitations In any job that contains audio-only outputs, you can't use these features: + Job progress status update In any audio-only output, you can't use these features: + Captions + Still or motion graphic overlay (image inserter, motion image inserter)