Mp3File.h File Reference

Pure C++20 MPEG-1 Layer III (MP3) codec - decoder and encoder. More...

#include "AudioFile.h"
#include <algorithm>
#include <array>
#include <cmath>
#include <cstdint>
#include <cstring>
#include <fstream>
#include <vector>
#include <filesystem>

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Classes
class	dspark::Mp3File

Namespaces
namespace	dspark
	Main namespace for the DSPark framework.

Detailed Description

Pure C++20 MPEG-1 Layer III (MP3) codec - decoder and encoder.

Full MP3 codec supporting both reading and writing:

Decoder: Decodes MPEG-1 Layer III to normalised float [-1, 1].

• Sample rates: 32000, 44100, 48000 Hz
• Mono and stereo (including joint stereo with M/S and intensity)
• CBR and VBR, ID3v2 tag skipping
• getInfo() reports the delivery format (32-bit float); MP3 itself has no PCM bit depth

Encoder: Encodes float audio to MPEG-1 Layer III CBR.

• Bitrates: 32-320 kbps (CBR); AudioFileInfo::bitsPerSample carries the requested bitrate in kbps and snaps to the nearest legal value
• Mono and stereo; the sample rate snaps to 32000/44100/48000 Hz
• Analysis polyphase filterbank + MDCT + Huffman coding, rate-controlled by a uniform global-gain search (no psychoacoustic model)
• Produces standard-compliant MP3 playable by any decoder

Warning

DECODE-ALL ARCHITECTURE: Because MP3 uses a backward-referencing Bit Reservoir, random-access streaming is non-trivial. openRead() decodes the ENTIRE FILE into RAM (input capped at 256 MB). This operation takes time and blocks the thread. NEVER call openRead() from the real-time audio thread.

Threading: owner-managed. One instance serves one file from one thread at a time; no internal synchronization (see AudioFile.h).

Dependencies: IO/AudioFile.h (Core/AudioBuffer.h, Core/AudioSpec.h).

Definition in file Mp3File.h.