diff --git a/libavcodec/bitstream_filters.c b/libavcodec/bitstream_filters.c
index 640b821413..cc3895295e 100644
--- a/libavcodec/bitstream_filters.c
+++ b/libavcodec/bitstream_filters.c
@@ -42,6 +42,7 @@ extern const FFBitStreamFilter ff_h264_redundant_pps_bsf;
 extern const FFBitStreamFilter ff_hapqa_extract_bsf;
 extern const FFBitStreamFilter ff_hevc_metadata_bsf;
 extern const FFBitStreamFilter ff_hevc_mp4toannexb_bsf;
+extern const FFBitStreamFilter ff_iamf_stream_merge_bsf;
 extern const FFBitStreamFilter ff_iamf_stream_split_bsf;
 extern const FFBitStreamFilter ff_imx_dump_header_bsf;
 extern const FFBitStreamFilter ff_media100_to_mjpegb_bsf;
diff --git a/libavcodec/bsf/Makefile b/libavcodec/bsf/Makefile
index 80dcdf94fb..34e26f1bc4 100644
--- a/libavcodec/bsf/Makefile
+++ b/libavcodec/bsf/Makefile
@@ -21,6 +21,7 @@ OBJS-$(CONFIG_HAPQA_EXTRACT_BSF)          += bsf/hapqa_extract.o
 OBJS-$(CONFIG_HEVC_METADATA_BSF)          += bsf/h265_metadata.o
 OBJS-$(CONFIG_HEVC_MP4TOANNEXB_BSF)       += bsf/hevc_mp4toannexb.o
 OBJS-$(CONFIG_IAMF_STREAM_MERGE_BSF)      += bsf/iamf_stream_merge_bsf.o
+OBJS-$(CONFIG_IAMF_STREAM_SPLIT_BSF)      += bsf/iamf_stream_split_bsf.o
 OBJS-$(CONFIG_IMX_DUMP_HEADER_BSF)        += bsf/imx_dump_header.o
 OBJS-$(CONFIG_MEDIA100_TO_MJPEGB_BSF)     += bsf/media100_to_mjpegb.o
 OBJS-$(CONFIG_MJPEG2JPEG_BSF)             += bsf/mjpeg2jpeg.o
diff --git a/libavcodec/bsf/iamf_stream_merge_bsf.c b/libavcodec/bsf/iamf_stream_merge_bsf.c
new file mode 100644
index 0000000000..c62698d374
--- /dev/null
+++ b/libavcodec/bsf/iamf_stream_merge_bsf.c
@@ -0,0 +1,227 @@
+/*
+ * Copyright (c) 2023 James Almer <jamrial@gmail.com>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <stdint.h>
+#include <stddef.h>
+
+#include "libavutil/dict.h"
+#include "libavutil/fifo.h"
+#include "libavutil/opt.h"
+#include "libavformat/iamf.h"
+#include "bsf.h"
+#include "bsf_internal.h"
+#include "bytestream.h"
+#include "get_bits.h"
+#include "put_bits.h"
+
+typedef struct IAMFMergeContext {
+    AVClass *class;
+
+    AVFifo *fifo;
+
+    // AVOptions
+    AVDictionary *index_mapping;
+    int stream_count;
+    int out_index;
+} IAMFMergeContext;
+
+static int find_id_from_idx(AVBSFContext *ctx, int idx)
+{
+    IAMFMergeContext *const c = ctx->priv_data;
+    const AVDictionaryEntry *e = NULL;
+
+    while (e = av_dict_iterate(c->index_mapping, e)) {
+        char *endptr = NULL;
+        int id, map_idx = strtol(e->key, &endptr, 0);
+        if (!endptr || *endptr)
+            return AVERROR_INVALIDDATA;
+        endptr = NULL;
+        id = strtol(e->value, &endptr, 0);
+        if (!endptr || *endptr)
+            return AVERROR_INVALIDDATA;
+        if (map_idx == idx)
+            return id;
+    }
+
+    av_log(ctx, AV_LOG_ERROR, "Invalid stream idx %d\n", idx);
+    return AVERROR_INVALIDDATA;
+}
+
+static int iamf_stream_merge_filter(AVBSFContext *ctx, AVPacket *out)
+{
+    IAMFMergeContext *const c = ctx->priv_data;
+    AVPacket *pkt;
+    int ret;
+
+    while (av_fifo_can_write(c->fifo)) {
+        ret = ff_bsf_get_packet(ctx, &pkt);
+        if (ret < 0)
+            return ret;
+        av_fifo_write(c->fifo, &pkt, 1);
+    }
+
+    pkt = NULL;
+    while (av_fifo_can_read(c->fifo)) {
+        PutBitContext pb;
+        PutByteContext p;
+        uint8_t *side_data, header[MAX_IAMF_OBU_HEADER_SIZE], obu[8];
+        unsigned int obu_header;
+        unsigned int skip_samples = 0, discard_padding = 0;
+        size_t side_data_size;
+        int header_size, obu_size, old_out_size = out->size;
+        int id, type;
+
+        av_packet_free(&pkt);
+        av_fifo_read(c->fifo, &pkt, 1);
+        id = find_id_from_idx(ctx, pkt->stream_index);
+        if (id < 0)
+            return AVERROR_INVALIDDATA;
+
+        type = id <= 17 ? id + IAMF_OBU_IA_AUDIO_FRAME_ID0 : IAMF_OBU_IA_AUDIO_FRAME;
+
+        side_data = av_packet_get_side_data(pkt, AV_PKT_DATA_SKIP_SAMPLES,
+                                            &side_data_size);
+
+        if (side_data && side_data_size >= 10) {
+            skip_samples = AV_RL32(side_data);
+            discard_padding = AV_RL32(side_data + 4);
+        }
+
+        init_put_bits(&pb, (uint8_t *)&obu_header, sizeof(obu_header));
+        put_bits(&pb, 5, type);
+        put_bits(&pb, 1, 0); // obu_redundant_copy
+        put_bits(&pb, 1, skip_samples || discard_padding);
+        put_bits(&pb, 1, 0); // obu_extension_flag
+        flush_put_bits(&pb);
+
+        init_put_bits(&pb, header, sizeof(header));
+        if (skip_samples || discard_padding) {
+            put_leb(&pb, discard_padding);
+            put_leb(&pb, skip_samples);
+        }
+        if (id > 17)
+            put_leb(&pb, id);
+        flush_put_bits(&pb);
+
+        header_size = put_bytes_count(&pb, 1);
+
+        init_put_bits(&pb, obu, sizeof(obu));
+        put_leb(&pb, header_size + pkt->size);
+        flush_put_bits(&pb);
+
+        obu_size = put_bytes_count(&pb, 1);
+
+        ret = av_grow_packet(out, 1 + obu_size + header_size + pkt->size);
+        if (ret < 0)
+            goto fail;
+
+        bytestream2_init_writer(&p, out->data + old_out_size, 1 + obu_size + header_size + pkt->size);
+        bytestream2_put_byteu(&p, obu_header);
+        bytestream2_put_bufferu(&p, obu, obu_size);
+        bytestream2_put_bufferu(&p, header, header_size);
+        bytestream2_put_bufferu(&p, pkt->data, pkt->size);
+    }
+
+    ret = av_packet_copy_props(out, pkt);
+    if (ret < 0)
+        goto fail;
+    out->stream_index = c->out_index;
+
+    ret = 0;
+fail:
+    av_packet_free(&pkt);
+    if (ret < 0)
+        av_packet_free(&out);
+    return ret;
+}
+
+static int iamf_stream_merge_init(AVBSFContext *ctx)
+{
+    IAMFMergeContext *const c = ctx->priv_data;
+
+    if (!c->index_mapping) {
+        av_log(ctx, AV_LOG_ERROR, "Empty index map\n");
+        return AVERROR(EINVAL);
+    }
+
+    c->fifo = av_fifo_alloc2(av_dict_count(c->index_mapping), sizeof(AVPacket*), 0);
+    if (!c->fifo)
+        return AVERROR(ENOMEM);
+
+    return 0;
+}
+
+static void iamf_stream_merge_flush(AVBSFContext *ctx)
+{
+    IAMFMergeContext *const c = ctx->priv_data;
+
+    while (av_fifo_can_read(c->fifo)) {
+        AVPacket *pkt;
+        av_fifo_read(c->fifo, &pkt, 1);
+        av_packet_free(&pkt);
+    }
+    av_fifo_reset2(c->fifo);
+}
+
+static void iamf_stream_merge_close(AVBSFContext *ctx)
+{
+    IAMFMergeContext *const c = ctx->priv_data;
+
+    if (c->fifo)
+        iamf_stream_merge_flush(ctx);
+    av_fifo_freep2(&c->fifo);
+}
+
+#define OFFSET(x) offsetof(IAMFMergeContext, x)
+#define FLAGS (AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_BSF_PARAM)
+static const AVOption iamf_stream_merge_options[] = {
+    { "index_mapping", "a :-separated list of stream_index=audio_substream_id entries "
+                       "to set stream id in output Audio Frame OBUs",
+        OFFSET(index_mapping), AV_OPT_TYPE_DICT, { .str = NULL }, 0, 0, FLAGS },
+    { "out_index", "Stream index to in output packets",
+        OFFSET(out_index), AV_OPT_TYPE_INT, { 0 }, 0, INT_MAX, FLAGS },
+    { NULL }
+};
+
+static const AVClass iamf_stream_merge_class = {
+    .class_name = "iamf_stream_merge_bsf",
+    .item_name  = av_default_item_name,
+    .option     = iamf_stream_merge_options,
+    .version    = LIBAVUTIL_VERSION_INT,
+};
+
+static const enum AVCodecID iamf_stream_merge_codec_ids[] = {
+    AV_CODEC_ID_PCM_S16LE, AV_CODEC_ID_PCM_S16BE,
+    AV_CODEC_ID_PCM_S24LE, AV_CODEC_ID_PCM_S24BE,
+    AV_CODEC_ID_PCM_S32LE, AV_CODEC_ID_PCM_S32BE,
+    AV_CODEC_ID_OPUS,      AV_CODEC_ID_AAC,
+    AV_CODEC_ID_FLAC,      AV_CODEC_ID_NONE,
+};
+
+const FFBitStreamFilter ff_iamf_stream_merge_bsf = {
+    .p.name         = "iamf_stream_merge",
+    .p.codec_ids    = iamf_stream_merge_codec_ids,
+    .p.priv_class   = &iamf_stream_merge_class,
+    .priv_data_size = sizeof(IAMFMergeContext),
+    .init           = iamf_stream_merge_init,
+    .flush          = iamf_stream_merge_flush,
+    .close          = iamf_stream_merge_close,
+    .filter         = iamf_stream_merge_filter,
+};
