rendobar · a-essawy · Jun 10, 2026 · Jun 10, 2026
diff --git a/guides/ffmpeg.mdx b/guides/ffmpeg.mdx
@@ -1,7 +1,7 @@
 ---
 title: "FFmpeg command guide"
 sidebarTitle: "FFmpeg"
 description: "Run any FFmpeg command in the cloud. ~120 whitelisted flags, 8-layer sandboxed execution, signed download URL. Same FFmpeg syntax you know."
 icon: "terminal"
 keywords: ["ffmpeg guide", "ffmpeg in cloud", "ffmpeg sandboxed execution", "ffmpeg flags whitelist", "ffmpeg command api"]
 ---
@@ -24,7 +24,7 @@
  }}
 />

 You write the FFmpeg command. Rendobar downloads inputs, runs the command in an isolated container, returns a signed download URL. Same syntax you'd run locally.

 ```bash
 curl -X POST https://api.rendobar.com/jobs \
@@ -40,15 +40,15 @@
 ```

 <Tip>
 From a shell? Use [the CLI](/cli/overview): `rb ffmpeg -i input.mp4 -vf scale=1280:720 out.mp4`. Local files upload automatically.
 </Tip>

 ## How it runs

 1. **Validate**: command parsed against 8 security layers (flag whitelist, format/filter blocklists)
 2. **Download**: input URLs pulled to a sandboxed worker
 3. **Substitute**: URLs replaced with local paths in the FFmpeg command
 4. **Execute**: FFmpeg runs in an isolated container with network disabled
 5. **Upload**: output goes to R2
 6. **Return**: signed `output.file.url` available via `GET /jobs/{id}`

@@ -67,21 +67,24 @@
 
 Reach for the `inputs` map only when a file can't go inline: a file a filter reads by name (see below), inline text you don't want to host, an already-uploaded asset, or when you need a stable filename. Each key is a filename staged under that exact name, and the command references it by bare name.
 
-A value can be one of four shapes:
+A value can be one of three shapes:
 
 | Value | Use it for |
 |---|---|
 | `"https://..."` | A remote file. Shorthand for `{ "url": "..." }` |
 | `{ "url": "https://..." }` | A remote file, explicit form |
 | `{ "content": "...text..." }` | Inline text you don't want to host (≤64 KB) |
-| `{ "ref": "asset_abc123" }` | A file you already uploaded, by its asset ID (returned by the uploads endpoint) |
+
+A file you already uploaded is referenced by its **content URL**: the `url`
+returned by the uploads endpoint, like `https://api.rendobar.com/assets/asset_abc123/content`.
+Pass it like any other URL.
 
 ```json
 {
   "type": "ffmpeg",
   "inputs": {
     "clip.mp4": "https://example.com/clip.mp4",
-    "logo.png": { "ref": "asset_brandlogo" }
+    "logo.png": "https://api.rendobar.com/assets/asset_brandlogo/content"
   },
   "params": {
     "command": "ffmpeg -i clip.mp4 -i logo.png -filter_complex overlay=10:10 output.mp4"
@@ -91,7 +94,7 @@

 ### Auxiliary files read by a filter

 Some files aren't passed as `-i` arguments. Filters like `subtitles=`, `lut3d=`, and `drawtext fontfile=`, and the lists read by the `concat` demuxer, read a file by name from the working directory. Provide those through `inputs` so they're staged before the command runs.

 This burns a subtitle track that lives only in the request, with no file to host:

@@ -115,8 +118,8 @@
 | Field | Type | Required | Default | Notes |
 |---|---|---|---|---|
 | `type` | string | yes | - | `"ffmpeg"` |
-| `inputs` | object | yes | - | Working directory for the command. Maps a filename to a source (URL, `{url}`, `{content}`, or `{ref}`). `{}` when every input is an inline `-i` URL. See [Input sources](#input-sources) |
+| `inputs` | object | yes | - | Working directory for the command. Maps a filename to a source (URL, `{url}`, or `{content}`; an uploaded asset's content URL is just a URL). `{}` when every input is an inline `-i` URL. See [Input sources](#input-sources) |
 | `params.command` | string | yes | - | Real FFmpeg command starting with `ffmpeg`. Input URLs go in `-i` positions |
 | `params.outputFormat` | string | no | inferred | Override container format. Inferred from trailing filename if omitted |
 | `params.timeout` | int | no | `120` | Server-side max execution in seconds. Range 1–900 |

@@ -140,13 +143,13 @@
 |---|---|
 | `-i` | Input file |
 | `-f` | Force format |
 | `-c:v`, `-c:a` | Video / audio codec (stream specifiers like `-c:v:0` work) |
 | `-vf`, `-af` | Video / audio filter |
 | `-filter_complex` | Complex filter graph |
 | `-map` | Stream mapping |
 | `-ss`, `-t` | Seek position, duration |
 | `-r`, `-s` | Frame rate, resolution |
 | `-b:v`, `-b:a` | Video / audio bitrate |
 | `-crf`, `-preset` | Quality + preset |
 | `-an`, `-vn` | Disable audio / video |
 | `-y` | Overwrite output |
@@ -158,14 +161,14 @@

 Every command is validated before it runs, then executed in an isolated, network-restricted sandbox.

 - **Flag allowlist.** Only known-safe flags pass. Anything unrecognised is rejected with `VALIDATION_ERROR` before dispatch.
 - **No reads through filters.** Filters and formats that read from disk, fetch over the network, or run external code are blocked.
 - **Path containment.** Inputs are limited to the files you provide. Path traversal and access to system paths are rejected.
 - **Sandboxed execution.** Each job runs in an isolated container with a clean environment, restricted I/O, and no ambient network access.

 ## Cost & timeout

 Priced per compute second from your [credit balance](/concepts/credits), the wall-clock time FFmpeg ran, excluding file transfer. Typical cost ~$0.05/min.

 Plan timeouts: 5 min (Free), 15 min (Pro). See [plan limits](/support/limits) for the full table. Exceeding the timeout returns `PROVIDER_TIMEOUT`; no credits charged.

@@ -223,9 +226,9 @@

 The filenames your command writes define the output. You get back every file it produced.

 Every completed job, FFmpeg or otherwise, returns the same `output` shape. [Job output](/concepts/job-output) documents it in full. The short version:

 - `output.data`: the computed answer (a probe result, a transcript). `null` for FFmpeg jobs, which only write files.
 - `output.file`: the headline result you play or download, one file or a stream manifest. `null` for pure file sets.
 - `output.files`: every file the job produced, the complete list.
 - `output.expiresAt`: Unix ms when the URLs expire, present when `files` is non-empty.
@@ -326,7 +329,7 @@

 ## Error handling

 A failed job carries an `error` object with `code`, `message`, `detail`, and `retryable`. When FFmpeg exits non-zero, `error.detail` holds the last ~2 KB of the real stderr. Fetch the job to see exactly why FFmpeg stopped.

 ```json
 {

diff --git a/job-types/ffmpeg.mdx b/job-types/ffmpeg.mdx
@@ -1,7 +1,7 @@
 ---
 title: "FFmpeg reference"
 sidebarTitle: "FFmpeg"
 description: "Execute a custom FFmpeg command via API with ~120 whitelisted flags, sandboxed execution, and signed output URL. Live on all plans, ~$0.05/min."
 icon: "terminal"
 tag: "Live"
 keywords: ["ffmpeg api reference", "ffmpeg cloud", "ffmpeg sandboxed", "ffmpeg rest api", "ffmpeg command api"]
@@ -14,7 +14,7 @@
      "@context": "https://schema.org",
      "@type": "TechArticle",
      "@id": "https://rendobar.com/docs/job-types/ffmpeg/#article",
      "headline": "FFmpeg reference",
      "description": "Execute a custom FFmpeg command with whitelisted flags, sandboxed execution, and signed output URL. Live on all plans.",
      "datePublished": "2026-03-20",
      "dateModified": "2026-05-24",
@@ -29,7 +29,7 @@
 **Live.** Production-ready, available on all plans.
 </Check>

 Execute a custom FFmpeg command with whitelisted flags. The `inputs` map stages source files into the working directory by name. The command references them by bare name, and inline `-i` URLs also work.

 <Info>
 **Timeout:** 900 s max (plan-capped) · **Accepts:** video, audio, image
@@ -100,10 +100,10 @@
      `{ "url": "https://..." }`. Remote file, explicit form.
    </ResponseField>
     <ResponseField name="content" type="object">
       `{ "content": "...text..." }`. Inline text staged verbatim, up to 64 KB. For subtitles, `concat` lists, and LUTs with nothing to host.
     </ResponseField>
-    <ResponseField name="ref" type="object">
-      `{ "ref": "asset_abc123" }`. A file you already uploaded, by its asset ID (returned by the uploads endpoint).
+    <ResponseField name="uploaded file" type="string">
+      A file you already uploaded is referenced by its content URL: the `url` returned by the uploads endpoint, like `https://api.rendobar.com/assets/asset_abc123/content`. Pass it like any other URL string.
     </ResponseField>
   </Expandable>
 
@@ -111,7 +111,7 @@
 </ParamField>

 <ParamField body="command" type="string" required>
  Real FFmpeg command starting with `ffmpeg`. Input URLs go in `-i` positions, or reference staged `inputs` files by name.
 </ParamField>

 <ParamField body="outputFormat" type="enum" default="inferred">
@@ -130,7 +130,7 @@

 Poll `GET /jobs/{id}` until `status: "complete"`. On success the job carries an `output` object. On failure it carries an `error` object. The filenames your command writes define the output.

 `output` is one shape for every job type, documented in full on [Job output](/concepts/job-output). FFmpeg jobs set `output.data` to `null` and return their files in `output.file` and `output.files`. Read `output.file.url` for the file to play or download, and `output.files` for the full list.

 <ResponseField name="error" type="object">
  Present when `status` is `failed`.
@@ -166,4 +166,4 @@
 - [CLI overview](/cli/overview): the same job from your terminal with `rb ffmpeg`
 - [Credits and billing](/concepts/credits): per-compute-second pricing detail
 - [Plan limits](/support/limits): file-size caps, timeouts, and concurrency per plan
 - [FFmpeg in the cloud](https://rendobar.com/ffmpeg/): every operation Rendobar supports