The Linux AppImage bundles its own GStreamer runtime, so no codec packages are needed on the host.
What plays
- Containers: MP4, MOV, M4V, MKV, WebM and AVI.
- Video: H.264, H.265 and the HAP family. H.264 and H.265 decode on the CPU. Other codecs are untested.
- Still images: PNG, JPG and static WebP. Animated GIF and animated WebP are not supported.
- Audio: none. Clips play silently and their audio tracks are ignored.
- HDR: not supported. Showout does not tone-map, so convert HDR clips to SDR first.
- Transparency: use HAP Alpha.
Why prepare clips
Most camera and download files are long-GOP H.264 or H.265. To land on a frame, the decoder starts at the previous keyframe and decodes forward. During live scrubbing that shows up as a half-second to one-second catch-up on some clips.
Prepared clips avoid it. HAP stores every frame on its own. Short-GOP H.264 keeps keyframes close together.
Choose a HAP variant
| Variant | Use it for |
|---|---|
| HAP Q | Final show clips at 1080p. Best quality, largest files. |
| HAP | 4K clips, loops and background content. About half the disk and GPU load of HAP Q. |
| HAP Alpha | Overlays that need transparency. |
At 4K, prefer HAP over HAP Q. HAP Q reads about twice the data per frame.
Encode with ffmpeg
Your ffmpeg needs the HAP encoder. Check with ffmpeg -h encoder=hap.
HAP Q:
ffmpeg -i source.mp4 -c:v hap -format hap_q -chunks 8 source.hapq.mov
HAP:
ffmpeg -i source.mp4 -c:v hap -chunks 8 source.hap.mov
HAP Alpha, from a source that has an alpha channel:
ffmpeg -i source.mov -c:v hap -format hap_alpha -chunks 8 source.hap_alpha.mov
Short-GOP H.264, when file size matters more than scrubbing:
ffmpeg -i source.mp4 -c:v libx264 -crf 18 -g 30 -keyint_min 30 -sc_threshold 0 -bf 0 source.shortgop.mp4
Keep the originals for editing. Load the prepared copies in Showout.
Other HAP formats
HapM, HapA and HAP R also play, on GPUs with BC texture support. HapA plays as a white alpha mask. Stock ffmpeg cannot create these formats.
Library badges
Sources and clip cells label prepared clips HAP, HAP Q, HAP Alpha or HAP R.
For H.264 and H.265, SHORT GOP means the clip is ready for scrubbing and PREP RECOMMENDED means it should be converted. These two badges need ffprobe installed on your system. Without it, clips still load and play.
Missing media
Templates store media paths, not the media itself. When clips are missing, cells show MISSING. Use File → Locate Missing Media…, then LOCATE FOLDER to relink a whole folder or RELINK for one cell. Stop the output before relinking.
Keep show media on a local SSD. Network and USB paths can disappear or stall mid-show.