Media Playback in OpenClaw

OpenClaw chat clients render assistant audio and video attachments directly in the conversation. The Gateway restricts those attachments to session-level access, delivers seekable byte ranges, and can generate a portable playback rendition for recognized formats that may not be universally safe across clients.

This page explains playback behavior in OpenClaw clients. Channel delivery, inbound media interpretation, and real-time voice conversations follow separate mechanisms; refer to Image and media support, Media understanding, and Talk mode.

Client support

Client	Playback path	Operator notes
Control UI	Themed inline audio cards and native video controls	Audio cards offer play/pause, seek, elapsed and total time, download, a voice-note badge, and keyboard controls. Space toggles playback; Left/Right seek by five seconds. Starting one audio card pauses the previous one. Video upload is available from the chat attachment picker.
iOS and macOS	`AVAudioPlayer` for audio and `AVPlayer` for video	Inline media coordinates with Talk and Listen so two speech paths do not play over each other. For a pinned-TLS Gateway, the app performs a bounded authenticated download before video playback instead of bypassing certificate pinning.
Android	Media3 ExoPlayer	The app streams video through the authenticated Gateway HTTP client, requests Android audio focus, and coordinates attachment playback with Talk/TTS. Cached transcript media rows remain visible offline, but playback needs a connection to obtain a fresh media ticket.
Linux companion	Control UI inside the companion WebView	Codec availability comes from GStreamer. Released packages include or declare the expected codec plugins; see Linux media codecs.

Portable formats

The Gateway treats these formats as the portable native set shared by the browser, Apple players, and Android Media3:

Kind	Portable native input	Recognized transcode input	Playback target
Audio	MP3; AAC in M4A/MP4; PCM WAV	AAC, AIFF, AMR/AMR-WB, CAF, FLAC, Ogg/Opus/Vorbis, WebM audio, WMA	AAC in M4A (`audio/mp4`)
Video	H.264 MP4 with a portable profile and 4:2:0 pixel format; AAC or MP3 audio when present	AVI, FLV, Matroska/MKV, QuickTime/MOV, WebM, ASF, WMV	H.264/AAC MP4 with 4:2:0 pixel format, at most 1920×1080

The Linux companion can also play formats supplied by its installed GStreamer plugins. Browser and operating-system updates may add native formats, but the table above is the cross-client contract OpenClaw targets.

Lazy playback renditions

Both Gateway byte routes accept ?playback=1: the managed attachment route under /api/chat/media/outgoing/.../full and the Control UI assistant-media route. Attachment metadata can report playback: "native" or playback: "transcode" so a client can choose the rendition deliberately.

Playback conversion is lazy:

A native source passes through unchanged.
A recognized non-portable source starts a bounded ffmpeg job. The route returns HTTP 202 with { "status": "preparing" } while the rendition is being prepared.
A later request receives the cached M4A or MP4 rendition.
If inspection or conversion is unavailable, fails, or exceeds a limit, the route falls back to the original bytes. The client can then show its unplayable-media fallback and keep the download action available.

Transcoding accepts sources up to 20 minutes and never raises the normal audio or video byte cap. Cached playback renditions are pruned by normal media-store maintenance.

Managed attachments and access

Agent-produced audio and video are stored as managed media artifacts. Images keep their separate managed-image artifact family. Native clients resolve the artifact through artifacts.download, which returns inline base64 bytes when the artifact is byte-backed or a short-lived, ticketed URL when it is Gateway-managed.

The ticketed byte routes support:

Range requests with HTTP 206 Partial Content for seeking
ETag and If-Range for safe resume behavior
HEAD requests with the same content metadata and no response body

Do not copy a ticketed URL into durable configuration. Clients reacquire a ticket from the authenticated Gateway when needed.

Metadata and limits

Chat attachments may include sizeBytes, durationMs, width, and height. OpenClaw also uses ffprobe, when available, to fill audio duration and video duration/dimensions for media facts and the Control UI ?meta=1 availability probe. Probing is best-effort: a missing or failed probe leaves fields absent instead of rejecting the attachment.

Gateway-managed assistant attachments use these per-file caps:

Kind	Maximum size
Image	12 MiB
Audio	16 MiB
Video	16 MiB

These are playback/storage caps, not the separate media-understanding limits. For transcription and description limits, see Image and media support.

Troubleshooting

Duration or dimensions are missing

Check that ffprobe is installed on the Gateway host and visible on its PATH:

ffprobe -version

Playback of an already portable file can still work without metadata.

A recognized format downloads instead of playing

Check both media tools on the Gateway host:

ffmpeg -version
ffprobe -version

ffprobe classifies codecs and duration; ffmpeg creates the portable rendition. If either step cannot safely handle the source, OpenClaw serves the original file and the client keeps its fallback/download path.

Playback stays in preparing state

The first rendition request is asynchronous. Wait briefly and retry. Very large, longer than 20-minute, unprobeable, or unsupported sources remain on the original-byte fallback instead of blocking the Gateway.

Linux reports a codec error

Use the package and source-build instructions in Linux media codecs. The .deb depends on the required GStreamer plugin packages; the AppImage carries the media framework and codecs installed by the release build.

Android shows a media row while offline

That is expected. Android caches the transcript metadata, not the attachment bytes or its short-lived download capability. Reconnect, then play again so the app can request a new ticket.