konowebcodecs/src/bind/ffmpeg/bind.js

144 lines
3.6 KiB
JavaScript

/**
* Constants
*/
const NULL = 0;
const SIZE_I32 = Uint32Array.BYTES_PER_ELEMENT;
const DEFAULT_ARGS = ["./ffmpeg", "-nostdin", "-y"];
const DEFAULT_ARGS_FFPROBE = ["./ffprobe"];
Module["NULL"] = NULL;
Module["SIZE_I32"] = SIZE_I32;
Module["DEFAULT_ARGS"] = DEFAULT_ARGS;
Module["DEFAULT_ARGS_FFPROBE"] = DEFAULT_ARGS_FFPROBE;
/**
* Variables
*/
Module["ret"] = -1;
Module["timeout"] = -1;
Module["logger"] = () => {};
Module["progress"] = () => {};
/**
* Functions
*/
function stringToPtr(str) {
const len = Module["lengthBytesUTF8"](str) + 1;
const ptr = Module["_malloc"](len);
Module["stringToUTF8"](str, ptr, len);
return ptr;
}
function stringsToPtr(strs) {
const len = strs.length;
const ptr = Module["_malloc"](len * SIZE_I32);
for (let i = 0; i < len; i++) {
Module["setValue"](ptr + SIZE_I32 * i, stringToPtr(strs[i]), "i32");
}
return ptr;
}
function print(message) {
Module["logger"]({ type: "stdout", message });
}
function printErr(message) {
if (!message.startsWith("Aborted(native code called abort())"))
Module["logger"]({ type: "stderr", message });
}
function exec(..._args) {
const args = [...Module["DEFAULT_ARGS"], ..._args];
try {
Module["_ffmpeg"](args.length, stringsToPtr(args));
} catch (e) {
if (!e.message.startsWith("Aborted")) {
throw e;
}
}
return Module["ret"];
}
function ffprobe(..._args) {
const args = [...Module["DEFAULT_ARGS_FFPROBE"], ..._args];
try {
Module["_ffprobe"](args.length, stringsToPtr(args));
} catch (e) {
if (!e.message.startsWith("Aborted")) {
throw e;
}
}
return Module["ret"];
}
function setLogger(logger) {
Module["logger"] = logger;
}
function setTimeout(timeout) {
Module["timeout"] = timeout;
}
function setProgress(handler) {
Module["progress"] = handler;
}
function receiveProgress(progress, time) {
Module["progress"]({ progress, time });
}
function reset() {
Module["ret"] = -1;
Module["timeout"] = -1;
}
/**
* In multithread version of ffmpeg.wasm, the bootstrap process is like:
* 1. Execute ffmpeg-core.js
* 2. ffmpeg-core.js spawns workers by calling `new Worker("ffmpeg-core.worker.js")`
* 3. ffmpeg-core.worker.js imports ffmpeg-core.js
* 4. ffmpeg-core.js imports ffmpeg-core.wasm
*
* It is a straightforward process when all files are in the same location.
* But when files are in different location (or Blob URL), #4 fails because
* there is no way to pass custom ffmpeg-core.wasm URL to ffmpeg-core.worker.js
* when it imports ffmpeg-core.js in #3.
*
* To fix this issue, a hack here is leveraging mainScriptUrlOrBlob variable by
* adding wasmURL and workerURL in base64 format as query string. ex:
*
* http://example.com/ffmpeg-core.js#{btoa(JSON.stringify({"wasmURL": "...", "workerURL": "..."}))}
*
* Thus, we can successfully extract custom URLs using _locateFile funciton.
*/
function _locateFile(path, prefix) {
const mainScriptUrlOrBlob = Module["mainScriptUrlOrBlob"];
if (mainScriptUrlOrBlob) {
const { wasmURL, workerURL } = JSON.parse(
atob(mainScriptUrlOrBlob.slice(mainScriptUrlOrBlob.lastIndexOf("#") + 1))
);
if (path.endsWith(".wasm")) return wasmURL;
if (path.endsWith(".worker.js")) return workerURL;
}
return prefix + path;
}
Module["stringToPtr"] = stringToPtr;
Module["stringsToPtr"] = stringsToPtr;
Module["print"] = print;
Module["printErr"] = printErr;
Module["locateFile"] = _locateFile;
Module["exec"] = exec;
Module["ffprobe"] = ffprobe;
Module["setLogger"] = setLogger;
Module["setTimeout"] = setTimeout;
Module["setProgress"] = setProgress;
Module["reset"] = reset;
Module["receiveProgress"] = receiveProgress;