0775104b69
Sets up the foundational elements for the NewsCaster AI application. This includes: - Initializing the project with Vite and React. - Defining core types for articles and player state. - Configuring build tools and TypeScript. - Adding essential dependencies like React, Vite, and Google's Gemini API client. - Providing initial README instructions for running locally. - Setting up basic styling and structure in index.html. - Defining available voices and playback constants. - Implementing utility functions for audio handling.
59 lines
1.9 KiB
TypeScript
59 lines
1.9 KiB
TypeScript
/**
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* Converts a Base64 string (Raw PCM) to a Uint8Array.
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*/
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export const base64ToUint8Array = (base64: string): Uint8Array => {
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const binaryString = atob(base64);
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const len = binaryString.length;
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const bytes = new Uint8Array(len);
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for (let i = 0; i < len; i++) {
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bytes[i] = binaryString.charCodeAt(i);
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}
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return bytes;
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};
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/**
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* Wraps raw PCM data in a WAV container so it can be played by standard HTML5 Audio elements.
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* This allows us to use `playbackRate` with automatic pitch preservation.
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*/
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export const createWavBlob = (pcmData: Uint8Array, sampleRate: number = 24000): Blob => {
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const numChannels = 1;
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const bitsPerSample = 16;
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const byteRate = (sampleRate * numChannels * bitsPerSample) / 8;
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const blockAlign = (numChannels * bitsPerSample) / 8;
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const dataSize = pcmData.length;
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const chunkSize = 36 + dataSize;
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const buffer = new ArrayBuffer(44 + dataSize);
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const view = new DataView(buffer);
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// RIFF chunk descriptor
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writeString(view, 0, 'RIFF');
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view.setUint32(4, chunkSize, true);
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writeString(view, 8, 'WAVE');
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// fmt sub-chunk
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writeString(view, 12, 'fmt ');
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view.setUint32(16, 16, true); // Subchunk1Size (16 for PCM)
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view.setUint16(20, 1, true); // AudioFormat (1 for PCM)
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view.setUint16(22, numChannels, true); // NumChannels
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view.setUint32(24, sampleRate, true); // SampleRate
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view.setUint32(28, byteRate, true); // ByteRate
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view.setUint16(32, blockAlign, true); // BlockAlign
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view.setUint16(34, bitsPerSample, true); // BitsPerSample
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// data sub-chunk
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writeString(view, 36, 'data');
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view.setUint32(40, dataSize, true);
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// Write PCM data
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const dataView = new Uint8Array(buffer, 44);
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dataView.set(pcmData);
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return new Blob([buffer], { type: 'audio/wav' });
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};
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const writeString = (view: DataView, offset: number, string: string) => {
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for (let i = 0; i < string.length; i++) {
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view.setUint8(offset + i, string.charCodeAt(i));
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}
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}; |