Add Logging singleton to manually control Mediabunny's console output (fixes #415)

packages/aac-encoder/src/index.ts

@@ -6,9 +6,11 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/.
  */
 
+import { Logging } from 'mediabunny';
+
 const AAC_ENCODER_LOADED_SYMBOL = Symbol.for('@mediabunny/aac-encoder loaded');
 if ((globalThis as Record<symbol, unknown>)[AAC_ENCODER_LOADED_SYMBOL]) {
-	console.error(
+	Logging._error(
 		'[WARNING]\n@mediabunny/aac-encoder was loaded twice.'
 		+ ' This will likely cause the encoder not to work correctly.'
 		+ ' Check if multiple dependencies are importing different versions of @mediabunny/aac-encoder,'

packages/ac3/src/index.ts

@@ -6,9 +6,11 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/.
  */
 
+import { Logging } from 'mediabunny';
+
 const AC3_LOADED_SYMBOL = Symbol.for('@mediabunny/ac3 loaded');
 if ((globalThis as Record<symbol, unknown>)[AC3_LOADED_SYMBOL]) {
-	console.error(
+	Logging._error(
 		'[WARNING]\n@mediabunny/ac3 was loaded twice.'
 		+ ' This will likely cause the encoder/decoder not to work correctly.'
 		+ ' Check if multiple dependencies are importing different versions of @mediabunny/ac3,'

packages/flac-encoder/src/index.ts

@@ -6,9 +6,11 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/.
  */
 
+import { Logging } from 'mediabunny';
+
 const FLAC_ENCODER_LOADED_SYMBOL = Symbol.for('@mediabunny/flac-encoder loaded');
 if ((globalThis as Record<symbol, unknown>)[FLAC_ENCODER_LOADED_SYMBOL]) {
-	console.error(
+	Logging._error(
 		'[WARNING]\n@mediabunny/flac-encoder was loaded twice.'
 		+ ' This will likely cause the encoder not to work correctly.'
 		+ ' Check if multiple dependencies are importing different versions of @mediabunny/flac-encoder,'

packages/mp3-encoder/src/index.ts

@@ -6,7 +6,7 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/.
  */
 
-import { CustomAudioEncoder, AudioCodec, AudioSample, EncodedPacket, registerEncoder } from 'mediabunny';
+import { CustomAudioEncoder, AudioCodec, AudioSample, EncodedPacket, Logging, registerEncoder } from 'mediabunny';
 import { MP3_FRAME_HEADER_SIZE, readMp3FrameHeader, SAMPLING_RATES } from '../../../shared/mp3-misc';
 import type { WorkerCommand, WorkerResponse, WorkerResponseData } from './shared';
 // @ts-expect-error An esbuild plugin handles this, TypeScript doesn't need to understand
@@ -14,7 +14,7 @@ import createWorker from './encode.worker';
 
 const MP3_ENCODER_LOADED_SYMBOL = Symbol.for('@mediabunny/mp3-encoder loaded');
 if ((globalThis as Record<symbol, unknown>)[MP3_ENCODER_LOADED_SYMBOL]) {
-	console.error(
+	Logging._error(
 		'[WARNING]\n@mediabunny/mp3-encoder was loaded twice.'
 		+ ' This will likely cause the encoder not to work correctly.'
 		+ ' Check if multiple dependencies are importing different versions of @mediabunny/mp3-encoder,'

packages/server/README.md

@@ -279,6 +279,40 @@ return new VideoSample(pixels, {
 });
 ```
 
+## Controlling logging
+
+Especially in command-line applications you usually don't want Mediabunny interfering with your stdout and stderr output. Mediabunny provides ways to control its console output:
+```ts
+import { Logging, LogLevel } from 'mediabunny';
+
+// The default: Mediabunny can log errors, warnings, and information messages.
+Logging.level = LogLevel.Info;
+
+// Only log warnings and errors.
+Logging.level = LogLevel.Warnings;
+
+// Only log errors.
+Logging.level = LogLevel.Errors;
+
+// Don't log anything at all.
+Logging.level = LogLevel.None;
+```
+
+You can also hook into log events:
+```ts
+Logging.on('error', (args: unknown[]) => {
+	// Handle error message
+});
+
+Logging.on('warn', (args: unknown[]) => {
+	// Handle warning message
+});
+
+Logging.on('info', (args: unknown[]) => {
+	// Handle info message
+});
+```
+
 ## Implementation details
 
 `@mediabunny/server` uses [NodeAV](https://github.com/seydx/node-av) under the hood which provides N-API C bindings to FFmpeg's C API. Using NodeAV, this package implements [custom decoders and encoders](https://mediabunny.dev/guide/supported-formats-and-codecs#custom-coders) by directly using the APIs provided by `libavcodec`.

packages/server/src/index.ts

@@ -8,6 +8,7 @@
 
 import {
 	AudioSample,
+	Logging,
 	MaybePromise,
 	registerDecoder,
 	registerEncoder,
@@ -24,7 +25,7 @@ import { copyAudioSampleToAvFrame, AvFrameAudioSampleResource } from './audio-sa
 
 const SERVER_LOADED_SYMBOL = Symbol.for('@mediabunny/server loaded');
 if ((globalThis as Record<symbol, unknown>)[SERVER_LOADED_SYMBOL]) {
-	console.error(
+	Logging._error(
 		'[WARNING]\n@mediabunny/server was loaded twice.'
 		+ ' This will likely cause the package not to work correctly.'
 		+ ' Check if multiple dependencies are importing different versions of @mediabunny/server,'