In Eagle 3D Streaming, the codec is the format your application compresses the picture into before it is sent. It is set once, in the app configuration, and the default — H264 — is what every stream on the platform has always used. Changing it is worth doing only when you know what you are trading, because two separate things have to agree before a codec is actually used: the machine your app runs on has to be able to produce it, and each viewer's browser has to be able to play it.
If your app runs on Unreal Engine 5.7 and a viewer's stream closes on its own — most often a viewer on an unstable connection — switching that stream's codec to VP9 stops it. VP9 does not hit the driver bug behind those crashes. Apps on Unreal Engine 5.8 are already protected and need no change.
The trade-off is that VP9 looks slightly less sharp than the default (H264) and uses the streaming machine's CPU rather than its GPU. So switch to it where it matters:
The change reaches viewers the next time they open the stream; anyone already watching keeps the old codec until they reload.
If only one client is affected and you do not want other viewers to lose any sharpness, make two configurations — leave your normal one on the default, add a second set to VP9 — and share the VP9 link with the affected client only. Creating and naming configurations is covered in App configuration.
In the Control Panel the setting sits in the app configuration, in the Developer options, as Codec. Leaving it alone is a real answer: blank means H264, which is what your app already streams with.
| Choice | Who can encode it | Who can play it | What it costs |
|---|---|---|---|
| Default (H264) | Every machine in the fleet | Every browser, every phone, every tablet | Nothing. This is today's behaviour. |
| H264 | Every machine | Everything | The same as the default, stated explicitly rather than left implied. |
| AV1 | Only NVIDIA Ada (RTX 40-series, L4, L40S, RTX 4000–6000 Ada) and Blackwell (RTX 50-series) | Recent Chrome, Edge, Firefox and Safari. Older devices cannot. | Roughly 30–50% less bandwidth for the same picture, and a harder decode on the viewer's device. |
| VP9 | Every machine — it is encoded in software, on the CPU | Chrome, Edge, Firefox. Safari support is patchier. | CPU on the streaming machine instead of the GPU's video encoder, which competes with your application for the same cores. |
| VP8 | Every machine — software, on the CPU | Everything, including very old devices | The most bandwidth of the four for the same picture. A compatibility fallback, not a quality choice. |
Your application is launched on whichever machine is free when a viewer arrives, and those machines do not all have the same graphics card. AV1 encoding exists only on NVIDIA's Ada and Blackwell generations. A card one generation older can play AV1 perfectly well and still be unable to make it — decoding and encoding are separate pieces of silicon, and that is the single most common surprise with this setting.
Only AV1 is gated this way. H264 is encoded by every card the platform runs on, and VP9 and VP8 are encoded in software, so no graphics card can refuse them.
A codec the streaming machine can produce is still useless if the person watching cannot decode it. Browsers differ, and the same browser differs by device and by age — AV1 decoding arrived in Chrome and Edge years before it reached most phones.
The two checks are not alternatives. Each can only ever reduce the choice, never raise it, and the picture a viewer receives is whatever survives both.
| Machine can encode | Viewer can decode | The viewer receives |
|---|---|---|
| yes | yes | The codec you chose |
| yes | no | H264 |
| no | yes | H264 |
| no | no | H264 |
| yes | did not say | The codec you chose |
The numbers below are for the same picture at the same resolution and frame rate. A codec that needs less bandwidth is not simply better: the saving is paid for somewhere, either in the viewer's decoding effort or in the streaming machine's processor.
| H264 | AV1 | VP9 | VP8 | |
|---|---|---|---|---|
| Bandwidth for the same picture | The baseline | 30–50% less | 20–35% less | 10–20% more |
| Encoded by | The GPU's video encoder | The GPU's video encoder, Ada or newer only | The CPU | The CPU |
| Effect on your application's frame rate | None worth measuring | None worth measuring | Competes for CPU with your app | Competes for CPU with your app |
| Viewer's device has to work | Hardly at all — decoded in hardware everywhere | Harder. Older phones and laptops decode it in software, which drains battery | Moderate | Light |
| Where it is supported | Everywhere | Recent Chrome, Edge, Firefox, Safari | Chrome, Edge, Firefox; Safari patchier | Everywhere, including very old devices |
What a viewer notices is not the codec but what the stream does when their connection cannot keep up. Every codec gives up quality in the same order — first sharpness, then frame rate — but they reach that point at different speeds.
| The viewer's connection | H264 | AV1 | VP9 / VP8 |
|---|---|---|---|
| Fast and wired 25 Mbit/s and up |
Full quality. Nothing to gain by changing. | Full quality, using less of the connection. No visible difference. | Full quality. |
| Ordinary home broadband 10–25 Mbit/s |
Good. The usual case. | Good, and steadier under a shared connection — a second person streaming video is less likely to disturb it. | Good on VP9; VP8 is the first to soften. |
| Mobile or congested 3–10 Mbit/s |
Noticeably soft on detailed scenes. | The clearest advantage. The same bandwidth carries a sharper picture — provided the phone can decode it without overheating. | VP9 similar to H264; VP8 worse. |
| Poor or unstable under 3 Mbit/s, or a changing connection |
Soft, but it keeps going. The most predictable behaviour. | Better picture while it holds. A connection that changes frequently is harder on it than on H264. | VP8 is the most forgiving of a bad connection and the worst-looking on a good one. |
Because either side can substitute H264, the configuration alone does not tell you what a session streamed. Two places record it:
The rest of the settings this one sits beside, including predefined streaming quality.
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