Legacy viewer GIF: trade palette fidelity for decoders that only speak GIF89a
`legacy-viewer-jpg-gif` covers embedded WebViews, factory kiosks, and intranet IE-era hosts that decode GIF89a but choke on H.264 or HEIC. Memory and CPU ceilings are real: oversized canvases or long loops can OOM or stutter. Avoid fragile transparency tricks—JPEG sources lack alpha, and matte mismatches show halos on old compositors. Oversize typography and contrast because low-DPI panels smear anti-aliased captions after palette reduction.
Old WebView JPG to GIF: cap canvas and frames, validate on real devices not spoofed UA strings
- Publish a device matrix with maximum safe width, height, and frame count; downscale JPGs before quantization and flatten complex gradients where possible.
- Run a 10-minute soak on real hardware, logging dropped frames or decoder resets; capture OS and WebView versions beside the file hash.
- Ship a paired PNG still for troubleshooting plus a rollback URL on object storage instead of email attachments that expire.
JPG to GIF (legacy) FAQ
GIF plays once then freezes on an old Android WebView—should we tweak loop metadata, frame count, or disposal methods first?
Halve dimensions and remove transitional frames to rule out decoder performance first. If the issue persists, experiment with explicit finite loop counts and simpler disposal modes; exotic transparency composites are often unsupported. Always test on the exact container build, not desktop Chrome with spoofed user agents.
Embedded browsers fake Chrome’s user agent but still choke—how do we target safely?
Key off the host SDK version or a capability bit from native code instead of UA substrings. Ship a conservative GIF profile to embedded clients even if desktop users could handle more.
Kiosk tablets OOM on large GIFs—what hard limits help?
Bound width×height×frame count with safety margin against RGBA scratch buffers; reject jobs automatically when estimates exceed RAM budgets. Keep crash dumps tied to asset hashes for reproducibility.
Transparent-looking GIFs show black or white halos on old players—why?
JPEG sources lack alpha; matte colors disagree with playback backgrounds and premultiplication differs across engines. Prefer solid cards or re-shot assets on known matte colors instead of chasing perfect alpha on legacy stacks.
Offline bundles must include GIFs—how do we keep package size sane?
Maintain a separate low-frame offline build, pair each GIF with a PNG still, and ship delta updates instead of re-downloading the whole animation set on every release.