Add @mediabunny/aac-encoder extension package

packages/aac-encoder/src/bridge.c

@@ -0,0 +1,190 @@
+/*!
+ * Copyright (c) 2026-present, Vanilagy and contributors
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include <emscripten.h>
+#include <stdlib.h>
+#include <string.h>
+#include "libavcodec/avcodec.h"
+#include "libavutil/opt.h"
+#include "libavutil/channel_layout.h"
+#include "libavutil/log.h"
+
+typedef struct {
+	AVCodecContext *codec_ctx;
+	AVPacket *packet;
+	AVFrame *frame;
+	float *input_buffer;
+	int input_buffer_size;
+	int encoded_pts;
+	int encoded_duration;
+} EncoderContext;
+
+EMSCRIPTEN_KEEPALIVE
+EncoderContext *init_encoder(int channels, int sample_rate, int bitrate) {
+	av_log_set_level(AV_LOG_ERROR);
+
+	const AVCodec *codec = avcodec_find_encoder(AV_CODEC_ID_AAC);
+	if (!codec) return NULL;
+
+	AVCodecContext *codec_ctx = avcodec_alloc_context3(codec);
+	if (!codec_ctx) return NULL;
+
+	codec_ctx->sample_fmt = AV_SAMPLE_FMT_FLTP;
+	codec_ctx->sample_rate = sample_rate;
+	codec_ctx->bit_rate = bitrate;
+	codec_ctx->time_base = (AVRational){1, sample_rate};
+
+	AVChannelLayout layout;
+	av_channel_layout_default(&layout, channels);
+	av_channel_layout_copy(&codec_ctx->ch_layout, &layout);
+	av_channel_layout_uninit(&layout);
+
+	if (avcodec_open2(codec_ctx, codec, NULL) < 0) {
+		avcodec_free_context(&codec_ctx);
+		return NULL;
+	}
+
+	AVPacket *packet = av_packet_alloc();
+	if (!packet) {
+		avcodec_free_context(&codec_ctx);
+		return NULL;
+	}
+
+	AVFrame *frame = av_frame_alloc();
+	if (!frame) {
+		av_packet_free(&packet);
+		avcodec_free_context(&codec_ctx);
+		return NULL;
+	}
+
+	frame->format = AV_SAMPLE_FMT_FLTP;
+	frame->sample_rate = sample_rate;
+	frame->nb_samples = codec_ctx->frame_size;
+	av_channel_layout_copy(&frame->ch_layout, &codec_ctx->ch_layout);
+
+	if (av_frame_get_buffer(frame, 0) < 0) {
+		av_frame_free(&frame);
+		av_packet_free(&packet);
+		avcodec_free_context(&codec_ctx);
+		return NULL;
+	}
+
+	EncoderContext *ctx = malloc(sizeof(EncoderContext));
+	if (!ctx) {
+		av_frame_free(&frame);
+		av_packet_free(&packet);
+		avcodec_free_context(&codec_ctx);
+		return NULL;
+	}
+
+	ctx->codec_ctx = codec_ctx;
+	ctx->packet = packet;
+	ctx->frame = frame;
+	ctx->input_buffer = NULL;
+	ctx->input_buffer_size = 0;
+	ctx->encoded_pts = 0;
+	ctx->encoded_duration = 0;
+
+	return ctx;
+}
+
+EMSCRIPTEN_KEEPALIVE
+int get_encoder_frame_size(EncoderContext *ctx) {
+	return ctx->codec_ctx->frame_size;
+}
+
+EMSCRIPTEN_KEEPALIVE
+uint8_t *get_encoder_extradata(EncoderContext *ctx) {
+	return ctx->codec_ctx->extradata;
+}
+
+EMSCRIPTEN_KEEPALIVE
+int get_encoder_extradata_size(EncoderContext *ctx) {
+	return ctx->codec_ctx->extradata_size;
+}
+
+EMSCRIPTEN_KEEPALIVE
+float *get_encode_input_ptr(EncoderContext *ctx, int size) {
+	if (ctx->input_buffer_size < size) {
+		free(ctx->input_buffer);
+		ctx->input_buffer = malloc(size);
+		if (!ctx->input_buffer) {
+			ctx->input_buffer_size = 0;
+			return NULL;
+		}
+		ctx->input_buffer_size = size;
+	}
+	return ctx->input_buffer;
+}
+
+EMSCRIPTEN_KEEPALIVE
+int send_frame(EncoderContext *ctx, int pts) {
+	int channels = ctx->codec_ctx->ch_layout.nb_channels;
+	int frame_size = ctx->frame->nb_samples;
+
+	ctx->frame->pts = pts;
+
+	// Deinterleave f32 input into the frame's f32-planar planes
+	float *input = ctx->input_buffer;
+	for (int ch = 0; ch < channels; ch++) {
+		float *plane = (float *)ctx->frame->data[ch];
+		for (int i = 0; i < frame_size; i++) {
+			plane[i] = input[i * channels + ch];
+		}
+	}
+
+	return avcodec_send_frame(ctx->codec_ctx, ctx->frame);
+}
+
+EMSCRIPTEN_KEEPALIVE
+int receive_packet(EncoderContext *ctx) {
+	int ret = avcodec_receive_packet(ctx->codec_ctx, ctx->packet);
+	if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) {
+		return 0;
+	}
+	if (ret < 0) return ret;
+
+	ctx->encoded_pts = ctx->packet->pts;
+	ctx->encoded_duration = ctx->packet->duration;
+
+	return ctx->packet->size;
+}
+
+EMSCRIPTEN_KEEPALIVE
+void flush_encoder_start(EncoderContext *ctx) {
+	avcodec_send_frame(ctx->codec_ctx, NULL);
+}
+
+EMSCRIPTEN_KEEPALIVE
+void reset_encoder(EncoderContext *ctx) {
+	avcodec_flush_buffers(ctx->codec_ctx);
+}
+
+EMSCRIPTEN_KEEPALIVE
+uint8_t *get_encoded_data(EncoderContext *ctx) {
+	return ctx->packet->data;
+}
+
+EMSCRIPTEN_KEEPALIVE
+int get_encoded_pts(EncoderContext *ctx) {
+	return ctx->encoded_pts;
+}
+
+EMSCRIPTEN_KEEPALIVE
+int get_encoded_duration(EncoderContext *ctx) {
+	return ctx->encoded_duration;
+}
+
+EMSCRIPTEN_KEEPALIVE
+void close_encoder(EncoderContext *ctx) {
+	free(ctx->input_buffer);
+	av_frame_free(&ctx->frame);
+	av_packet_free(&ctx->packet);
+	avcodec_free_context(&ctx->codec_ctx);
+	free(ctx);
+}