📖 SlimCodec Client-Side Media Compression & Rate-Distortion Architecture
SlimCodec is a 100% client-side image, video, and audio compression workbench built on browser Canvas 2D, OfflineAudioContext, CompressionStream, and MediaRecorder, executing all encoding in local memory while uploading 0 bytes to any server.
SlimCodec combines PNG 256-color Median-Cut quantization with Deflate repackaging, WebP/JPEG rate-distortion encoding, 4-bit IMA ADPCM 4:1 audio compression, and VP9/MP4 video transcoding with live PSNR (dB) and SSIM telemetry across 4 languages and localStorage state.
🎛️ 本地媒体源与编码器参数
📊 实时率失真遥测 (PSNR / SSIM) 与双栏对比预览
🔬 Compress Images, Audio & Video Locally in 3 Steps with SlimCodec
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01 · Select Image, Audio, or Video Mode or Load Built-In Test Media
SlimCodec lets you drag and drop local PNG/JPEG/WebP, WAV/MP3/FLAC, or MP4/WebM files in the first of 3 steps, or click "Load Built-In Sample" to synthesize high-resolution test images, stereo chord audio, or 60fps video in 1 second with 0 bytes uploaded.
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02 · Configure Target Codec, Palette Depth, Sample Rate, or Bitrate
SlimCodec provides granular controls for image quality (1%–100%), PNG palette size (16–256 colors), audio sample rate (8 kHz–48 kHz) with 4-bit IMA ADPCM encoding, and MP4 video resolution (1080p/720p/480p) with target bitrates from 300 kbps to 2.5 Mbps and 0 bytes uploaded.
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03 · Inspect Byte Savings, PSNR/SSIM Metrics & Download Instantly
SlimCodec computes exact before/after byte counts, percentage reduction (%), PSNR (dB), SSIM, and audio SNR in milliseconds, offering side-by-side visual comparison, A/B audio playback, localStorage preset persistence, and 1-click local download.
❓ Client-Side Image, Audio & Video Compression FAQ
SlimCodec answers key engineering questions regarding browser-native PNG 256-color quantization, EXIF metadata removal, 4-bit IMA ADPCM audio compression, MP4 video bitrate transcoding, and 0 bytes privacy guarantees.
Does SlimCodec ever upload my private images, audio recordings, or videos to a server?
SlimCodec executes 100% of its image, audio, and video compression inside your browser memory using Canvas 2D, Web Audio API, CompressionStream, and MediaRecorder, uploading 0 bytes of media data to any external server over HTTPS.
How does SlimCodec PNG-8 Median-Cut compression shrink PNG files by 60%–80%?
SlimCodec partitions 32-bit RGBA pixels into an optimal 16-to-256 color PLTE/tRNS indexed palette via Median-Cut quantization and Floyd-Steinberg dithering before Deflate compression, reducing each pixel from 4 bytes to 1 byte while keeping PSNR above 36 dB.
What is the advantage of 4-Bit IMA ADPCM WAV over standard 16-Bit PCM WAV in SlimCodec?
SlimCodec implements a compliant RIFF 0x0011 IMA ADPCM encoder that packs each 16-bit PCM sample delta into a 4-bit nibble (a deterministic 4:1 ratio); combined with 22.05 kHz mono resampling, a 10 MB recording shrinks to ~650 KB with native browser playback.
How does SlimCodec compress MP4 and WebM video directly in the browser without heavy plugins?
SlimCodec combines HTML5 Video decoding, Canvas frame-rate sampling, and hardware-accelerated MediaRecorder encoders (VP9/VP8/H.264) to cap frame rates at 24–30 fps and bitrates at 300 kbps–2.5 Mbps, cutting video byte size by 50%–85% with 0 bytes uploaded.
What do the PSNR (dB) and SSIM quality scores mean after compressing an image?
SlimCodec calculates objective fidelity metrics in 10 ms with 0 bytes uploaded: a PSNR (Peak Signal-to-Noise Ratio) above 40 dB indicates visually lossless quality, 32–40 dB represents high-efficiency compression, and an SSIM score near 1.000 confirms preserved structural edges.