diff --git a/configure b/configure
index 6d1df83d50..2c635043dd 100755
--- a/configure
+++ b/configure
@@ -2517,6 +2517,7 @@ CONFIG_EXTRA="
     huffyuvdsp
     huffyuvencdsp
     iamfdec
+    iamfenc
     idctdsp
     iirfilter
     inflate_wrapper
@@ -3536,6 +3537,7 @@ hds_muxer_select="flv_muxer"
 hls_demuxer_select="adts_header ac3_parser mov_demuxer mpegts_demuxer"
 hls_muxer_select="mov_muxer mpegts_muxer"
 iamf_demuxer_select="iamfdec"
+iamf_muxer_select="iamfenc"
 image2_alias_pix_demuxer_select="image2_demuxer"
 image2_brender_pix_demuxer_select="image2_demuxer"
 imf_demuxer_deps="libxml2"
diff --git a/libavformat/Makefile b/libavformat/Makefile
index 3b83f5a685..4a380668bd 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -36,6 +36,7 @@ OBJS-$(HAVE_LIBC_MSVCRT)                 += file_open.o
 # subsystems
 OBJS-$(CONFIG_ISO_MEDIA)                 += isom.o
 OBJS-$(CONFIG_IAMFDEC)                   += iamf_reader.o iamf_parse.o iamf.o
+OBJS-$(CONFIG_IAMFENC)                   += iamf_writer.o iamf.o
 OBJS-$(CONFIG_NETWORK)                   += network.o
 OBJS-$(CONFIG_RIFFDEC)                   += riffdec.o
 OBJS-$(CONFIG_RIFFENC)                   += riffenc.o
@@ -260,7 +261,7 @@ OBJS-$(CONFIG_HLS_DEMUXER)               += hls.o hls_sample_encryption.o
 OBJS-$(CONFIG_HLS_MUXER)                 += hlsenc.o hlsplaylist.o avc.o
 OBJS-$(CONFIG_HNM_DEMUXER)               += hnm.o
 OBJS-$(CONFIG_IAMF_DEMUXER)              += iamfdec.o
-OBJS-$(CONFIG_IAMF_MUXER)                += iamfenc.o iamf_writer.o iamf.o
+OBJS-$(CONFIG_IAMF_MUXER)                += iamfenc.o
 OBJS-$(CONFIG_ICO_DEMUXER)               += icodec.o
 OBJS-$(CONFIG_ICO_MUXER)                 += icoenc.o
 OBJS-$(CONFIG_IDCIN_DEMUXER)             += idcin.o
diff --git a/libavformat/iamf_writer.c b/libavformat/iamf_writer.c
index a807fed786..9ed20fc562 100644
--- a/libavformat/iamf_writer.c
+++ b/libavformat/iamf_writer.c
@@ -852,3 +852,225 @@ int ff_iamf_write_descriptors(const IAMFContext *iamf, AVIOContext *pb, void *lo
 
     return 0;
 }
+
+static int write_parameter_block(const IAMFContext *iamf, AVIOContext *pb,
+                                 const AVIAMFParamDefinition *param, void *log_ctx)
+{
+    uint8_t header[MAX_IAMF_OBU_HEADER_SIZE];
+    IAMFParamDefinition *param_definition = ff_iamf_get_param_definition(iamf, param->parameter_id);
+    PutBitContext pbc;
+    AVIOContext *dyn_bc;
+    uint8_t *dyn_buf = NULL;
+    int dyn_size, ret;
+
+    if (param->type > AV_IAMF_PARAMETER_DEFINITION_RECON_GAIN) {
+        av_log(log_ctx, AV_LOG_DEBUG, "Ignoring side data with unknown type %u\n",
+               param->type);
+        return 0;
+    }
+
+    if (!param_definition) {
+        av_log(log_ctx, AV_LOG_ERROR, "Non-existent Parameter Definition with ID %u referenced by a packet\n",
+               param->parameter_id);
+        return AVERROR(EINVAL);
+    }
+
+    if (param->type != param_definition->param->type) {
+        av_log(log_ctx, AV_LOG_ERROR, "Inconsistent values for Parameter Definition "
+                                "with ID %u in a packet\n",
+               param->parameter_id);
+        return AVERROR(EINVAL);
+    }
+
+    ret = avio_open_dyn_buf(&dyn_bc);
+    if (ret < 0)
+        return ret;
+
+    // Sequence Header
+    init_put_bits(&pbc, header, sizeof(header));
+    put_bits(&pbc, 5, IAMF_OBU_IA_PARAMETER_BLOCK);
+    put_bits(&pbc, 3, 0);
+    flush_put_bits(&pbc);
+    avio_write(pb, header, put_bytes_count(&pbc, 1));
+
+    ffio_write_leb(dyn_bc, param->parameter_id);
+    if (!param_definition->mode) {
+        ffio_write_leb(dyn_bc, param->duration);
+        ffio_write_leb(dyn_bc, param->constant_subblock_duration);
+        if (param->constant_subblock_duration == 0)
+            ffio_write_leb(dyn_bc, param->nb_subblocks);
+    }
+
+    for (int i = 0; i < param->nb_subblocks; i++) {
+        const void *subblock = av_iamf_param_definition_get_subblock(param, i);
+
+        switch (param->type) {
+        case AV_IAMF_PARAMETER_DEFINITION_MIX_GAIN: {
+            const AVIAMFMixGain *mix = subblock;
+            if (!param_definition->mode && param->constant_subblock_duration == 0)
+                ffio_write_leb(dyn_bc, mix->subblock_duration);
+
+            ffio_write_leb(dyn_bc, mix->animation_type);
+
+            avio_wb16(dyn_bc, rescale_rational(mix->start_point_value, 1 << 8));
+            if (mix->animation_type >= AV_IAMF_ANIMATION_TYPE_LINEAR)
+                avio_wb16(dyn_bc, rescale_rational(mix->end_point_value, 1 << 8));
+            if (mix->animation_type == AV_IAMF_ANIMATION_TYPE_BEZIER) {
+                avio_wb16(dyn_bc, rescale_rational(mix->control_point_value, 1 << 8));
+                avio_w8(dyn_bc, av_clip_uint8(av_rescale(mix->control_point_relative_time.num, 1 << 8,
+                                                         mix->control_point_relative_time.den)));
+            }
+            break;
+        }
+        case AV_IAMF_PARAMETER_DEFINITION_DEMIXING: {
+            const AVIAMFDemixingInfo *demix = subblock;
+            if (!param_definition->mode && param->constant_subblock_duration == 0)
+                ffio_write_leb(dyn_bc, demix->subblock_duration);
+
+            avio_w8(dyn_bc, demix->dmixp_mode << 5);
+            break;
+        }
+        case AV_IAMF_PARAMETER_DEFINITION_RECON_GAIN: {
+            const AVIAMFReconGain *recon = subblock;
+            const AVIAMFAudioElement *audio_element = param_definition->audio_element->celement;
+
+            if (!param_definition->mode && param->constant_subblock_duration == 0)
+                ffio_write_leb(dyn_bc, recon->subblock_duration);
+
+            if (!audio_element) {
+                av_log(log_ctx, AV_LOG_ERROR, "Invalid Parameter Definition with ID %u referenced by a packet\n", param->parameter_id);
+                return AVERROR(EINVAL);
+            }
+
+            for (int j = 0; j < audio_element->nb_layers; j++) {
+                const AVIAMFLayer *layer = audio_element->layers[j];
+
+                if (layer->flags & AV_IAMF_LAYER_FLAG_RECON_GAIN) {
+                    unsigned int recon_gain_flags = 0;
+                    int k = 0;
+
+                    for (; k < 7; k++)
+                        recon_gain_flags |= (1 << k) * !!recon->recon_gain[j][k];
+                    for (; k < 12; k++)
+                        recon_gain_flags |= (2 << k) * !!recon->recon_gain[j][k];
+                    if (recon_gain_flags >> 8)
+                        recon_gain_flags |= (1 << k);
+
+                    ffio_write_leb(dyn_bc, recon_gain_flags);
+                    for (k = 0; k < 12; k++) {
+                        if (recon->recon_gain[j][k])
+                            avio_w8(dyn_bc, recon->recon_gain[j][k]);
+                    }
+                }
+            }
+            break;
+        }
+        default:
+            av_assert0(0);
+        }
+    }
+
+    dyn_size = avio_get_dyn_buf(dyn_bc, &dyn_buf);
+    ffio_write_leb(pb, dyn_size);
+    avio_write(pb, dyn_buf, dyn_size);
+    ffio_free_dyn_buf(&dyn_bc);
+
+    return 0;
+}
+
+int ff_iamf_write_parameter_blocks(const IAMFContext *iamf, AVIOContext *pb,
+                                   AVPacket *pkt, void *log_ctx)
+{
+    AVIAMFParamDefinition *mix =
+        (AVIAMFParamDefinition *)av_packet_get_side_data(pkt,
+                                                         AV_PKT_DATA_IAMF_MIX_GAIN_PARAM,
+                                                         NULL);
+    AVIAMFParamDefinition *demix =
+        (AVIAMFParamDefinition *)av_packet_get_side_data(pkt,
+                                                         AV_PKT_DATA_IAMF_DEMIXING_INFO_PARAM,
+                                                         NULL);
+    AVIAMFParamDefinition *recon =
+        (AVIAMFParamDefinition *)av_packet_get_side_data(pkt,
+                                                         AV_PKT_DATA_IAMF_RECON_GAIN_INFO_PARAM,
+                                                         NULL);
+
+    if (mix) {
+        int ret = write_parameter_block(iamf, pb, mix, log_ctx);
+        if (ret < 0)
+           return ret;
+    }
+    if (demix) {
+        int ret = write_parameter_block(iamf, pb, demix, log_ctx);
+        if (ret < 0)
+            return ret;
+    }
+    if (recon) {
+        int ret = write_parameter_block(iamf, pb, recon, log_ctx);
+        if (ret < 0)
+           return ret;
+    }
+
+    return 0;
+}
+
+int ff_iamf_write_audio_frame(const IAMFContext *iamf, AVIOContext *pb,
+                              unsigned audio_substream_id, AVPacket *pkt)
+{
+    uint8_t header[MAX_IAMF_OBU_HEADER_SIZE];
+    PutBitContext pbc;
+    AVIOContext *dyn_bc;
+    uint8_t *side_data, *dyn_buf = NULL;
+    unsigned int skip_samples = 0, discard_padding = 0;
+    size_t side_data_size;
+    int dyn_size, type = audio_substream_id <= 17 ?
+                         audio_substream_id + IAMF_OBU_IA_AUDIO_FRAME_ID0 : IAMF_OBU_IA_AUDIO_FRAME;
+    int ret;
+
+    if (!pkt->size) {
+        uint8_t *new_extradata = av_packet_get_side_data(pkt,
+                                                         AV_PKT_DATA_NEW_EXTRADATA,
+                                                         NULL);
+
+        if (!new_extradata)
+            return AVERROR_INVALIDDATA;
+
+        // TODO: update FLAC Streaminfo on seekable output
+        return 0;
+    }
+
+    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);
+    }
+
+    ret = avio_open_dyn_buf(&dyn_bc);
+    if (ret < 0)
+        return ret;
+
+    init_put_bits(&pbc, header, sizeof(header));
+    put_bits(&pbc, 5, type);
+    put_bits(&pbc, 1, 0); // obu_redundant_copy
+    put_bits(&pbc, 1, skip_samples || discard_padding);
+    put_bits(&pbc, 1, 0); // obu_extension_flag
+    flush_put_bits(&pbc);
+    avio_write(pb, header, put_bytes_count(&pbc, 1));
+
+    if (skip_samples || discard_padding) {
+        ffio_write_leb(dyn_bc, discard_padding);
+        ffio_write_leb(dyn_bc, skip_samples);
+    }
+
+    if (audio_substream_id > 17)
+        ffio_write_leb(dyn_bc, audio_substream_id);
+
+    dyn_size = avio_get_dyn_buf(dyn_bc, &dyn_buf);
+    ffio_write_leb(pb, dyn_size + pkt->size);
+    avio_write(pb, dyn_buf, dyn_size);
+    ffio_free_dyn_buf(&dyn_bc);
+    avio_write(pb, pkt->data, pkt->size);
+
+    return 0;
+}
diff --git a/libavformat/iamf_writer.h b/libavformat/iamf_writer.h
index 24f1c14769..671d9cc11d 100644
--- a/libavformat/iamf_writer.h
+++ b/libavformat/iamf_writer.h
@@ -24,6 +24,7 @@
 
 #include <stddef.h>
 
+#include "libavcodec/packet.h"
 #include "avformat.h"
 #include "avio.h"
 #include "iamf.h"
@@ -47,4 +48,9 @@ int ff_iamf_add_mix_presentation(IAMFContext *iamf, const AVStreamGroup *stg, vo
 
 int ff_iamf_write_descriptors(const IAMFContext *iamf, AVIOContext *pb, void *log_ctx);
 
+int ff_iamf_write_parameter_blocks(const IAMFContext *iamf, AVIOContext *pb,
+                                   AVPacket *pkt, void *log_ctx);
+int ff_iamf_write_audio_frame(const IAMFContext *iamf, AVIOContext *pb,
+                              unsigned audio_substream_id, AVPacket *pkt);
+
 #endif /* AVFORMAT_IAMF_WRITER_H */
diff --git a/libavformat/iamfenc.c b/libavformat/iamfenc.c
index b5572c79af..72a7555c9a 100644
--- a/libavformat/iamfenc.c
+++ b/libavformat/iamfenc.c
@@ -133,219 +133,18 @@ static int iamf_write_header(AVFormatContext *s)
     return 0;
 }
 
-static inline int rescale_rational(AVRational q, int b)
-{
-    return av_clip_int16(av_rescale(q.num, b, q.den));
-}
-
-static int write_parameter_block(AVFormatContext *s, const AVIAMFParamDefinition *param)
-{
-    const IAMFMuxContext *const c = s->priv_data;
-    const IAMFContext *const iamf = &c->iamf;
-    uint8_t header[MAX_IAMF_OBU_HEADER_SIZE];
-    IAMFParamDefinition *param_definition = ff_iamf_get_param_definition(iamf, param->parameter_id);
-    PutBitContext pb;
-    AVIOContext *dyn_bc;
-    uint8_t *dyn_buf = NULL;
-    int dyn_size, ret;
-
-    if (param->type > AV_IAMF_PARAMETER_DEFINITION_RECON_GAIN) {
-        av_log(s, AV_LOG_DEBUG, "Ignoring side data with unknown type %u\n",
-               param->type);
-        return 0;
-    }
-
-    if (!param_definition) {
-        av_log(s, AV_LOG_ERROR, "Non-existent Parameter Definition with ID %u referenced by a packet\n",
-               param->parameter_id);
-        return AVERROR(EINVAL);
-    }
-
-    if (param->type != param_definition->param->type) {
-        av_log(s, AV_LOG_ERROR, "Inconsistent values for Parameter Definition "
-                                "with ID %u in a packet\n",
-               param->parameter_id);
-        return AVERROR(EINVAL);
-    }
-
-    ret = avio_open_dyn_buf(&dyn_bc);
-    if (ret < 0)
-        return ret;
-
-    // Sequence Header
-    init_put_bits(&pb, header, sizeof(header));
-    put_bits(&pb, 5, IAMF_OBU_IA_PARAMETER_BLOCK);
-    put_bits(&pb, 3, 0);
-    flush_put_bits(&pb);
-    avio_write(s->pb, header, put_bytes_count(&pb, 1));
-
-    ffio_write_leb(dyn_bc, param->parameter_id);
-    if (!param_definition->mode) {
-        ffio_write_leb(dyn_bc, param->duration);
-        ffio_write_leb(dyn_bc, param->constant_subblock_duration);
-        if (param->constant_subblock_duration == 0)
-            ffio_write_leb(dyn_bc, param->nb_subblocks);
-    }
-
-    for (int i = 0; i < param->nb_subblocks; i++) {
-        const void *subblock = av_iamf_param_definition_get_subblock(param, i);
-
-        switch (param->type) {
-        case AV_IAMF_PARAMETER_DEFINITION_MIX_GAIN: {
-            const AVIAMFMixGain *mix = subblock;
-            if (!param_definition->mode && param->constant_subblock_duration == 0)
-                ffio_write_leb(dyn_bc, mix->subblock_duration);
-
-            ffio_write_leb(dyn_bc, mix->animation_type);
-
-            avio_wb16(dyn_bc, rescale_rational(mix->start_point_value, 1 << 8));
-            if (mix->animation_type >= AV_IAMF_ANIMATION_TYPE_LINEAR)
-                avio_wb16(dyn_bc, rescale_rational(mix->end_point_value, 1 << 8));
-            if (mix->animation_type == AV_IAMF_ANIMATION_TYPE_BEZIER) {
-                avio_wb16(dyn_bc, rescale_rational(mix->control_point_value, 1 << 8));
-                avio_w8(dyn_bc, av_clip_uint8(av_rescale(mix->control_point_relative_time.num, 1 << 8,
-                                                         mix->control_point_relative_time.den)));
-            }
-            break;
-        }
-        case AV_IAMF_PARAMETER_DEFINITION_DEMIXING: {
-            const AVIAMFDemixingInfo *demix = subblock;
-            if (!param_definition->mode && param->constant_subblock_duration == 0)
-                ffio_write_leb(dyn_bc, demix->subblock_duration);
-
-            avio_w8(dyn_bc, demix->dmixp_mode << 5);
-            break;
-        }
-        case AV_IAMF_PARAMETER_DEFINITION_RECON_GAIN: {
-            const AVIAMFReconGain *recon = subblock;
-            const AVIAMFAudioElement *audio_element = param_definition->audio_element->celement;
-
-            if (!param_definition->mode && param->constant_subblock_duration == 0)
-                ffio_write_leb(dyn_bc, recon->subblock_duration);
-
-            if (!audio_element) {
-                av_log(s, AV_LOG_ERROR, "Invalid Parameter Definition with ID %u referenced by a packet\n", param->parameter_id);
-                return AVERROR(EINVAL);
-            }
-
-            for (int j = 0; j < audio_element->nb_layers; j++) {
-                const AVIAMFLayer *layer = audio_element->layers[j];
-
-                if (layer->flags & AV_IAMF_LAYER_FLAG_RECON_GAIN) {
-                    unsigned int recon_gain_flags = 0;
-                    int k = 0;
-
-                    for (; k < 7; k++)
-                        recon_gain_flags |= (1 << k) * !!recon->recon_gain[j][k];
-                    for (; k < 12; k++)
-                        recon_gain_flags |= (2 << k) * !!recon->recon_gain[j][k];
-                    if (recon_gain_flags >> 8)
-                        recon_gain_flags |= (1 << k);
-
-                    ffio_write_leb(dyn_bc, recon_gain_flags);
-                    for (k = 0; k < 12; k++) {
-                        if (recon->recon_gain[j][k])
-                            avio_w8(dyn_bc, recon->recon_gain[j][k]);
-                    }
-                }
-            }
-            break;
-        }
-        default:
-            av_assert0(0);
-        }
-    }
-
-    dyn_size = avio_get_dyn_buf(dyn_bc, &dyn_buf);
-    ffio_write_leb(s->pb, dyn_size);
-    avio_write(s->pb, dyn_buf, dyn_size);
-    ffio_free_dyn_buf(&dyn_bc);
-
-    return 0;
-}
-
 static int iamf_write_packet(AVFormatContext *s, AVPacket *pkt)
 {
     const IAMFMuxContext *const c = s->priv_data;
     AVStream *st = s->streams[pkt->stream_index];
-    uint8_t header[MAX_IAMF_OBU_HEADER_SIZE];
-    PutBitContext pb;
-    AVIOContext *dyn_bc;
-    uint8_t *side_data, *dyn_buf = NULL;
-    unsigned int skip_samples = 0, discard_padding = 0;
-    size_t side_data_size;
-    int dyn_size, type = st->id <= 17 ? st->id + IAMF_OBU_IA_AUDIO_FRAME_ID0 : IAMF_OBU_IA_AUDIO_FRAME;
-    int ret;
+    int ret = 0;
 
-    if (!pkt->size) {
-        uint8_t *new_extradata = av_packet_get_side_data(pkt, AV_PKT_DATA_NEW_EXTRADATA, NULL);
+    if (st->id == c->first_stream_id)
+        ret = ff_iamf_write_parameter_blocks(&c->iamf, s->pb, pkt, s);
+    if (!ret)
+        ret = ff_iamf_write_audio_frame(&c->iamf, s->pb, st->id, pkt);
 
-        if (!new_extradata)
-            return AVERROR_INVALIDDATA;
-
-        // TODO: update FLAC Streaminfo on seekable output
-        return 0;
-    }
-
-    if (s->nb_stream_groups && st->id == c->first_stream_id) {
-        AVIAMFParamDefinition *mix =
-            (AVIAMFParamDefinition *)av_packet_get_side_data(pkt, AV_PKT_DATA_IAMF_MIX_GAIN_PARAM, NULL);
-        AVIAMFParamDefinition *demix =
-            (AVIAMFParamDefinition *)av_packet_get_side_data(pkt, AV_PKT_DATA_IAMF_DEMIXING_INFO_PARAM, NULL);
-        AVIAMFParamDefinition *recon =
-            (AVIAMFParamDefinition *)av_packet_get_side_data(pkt, AV_PKT_DATA_IAMF_RECON_GAIN_INFO_PARAM, NULL);
-
-        if (mix) {
-            ret = write_parameter_block(s, mix);
-            if (ret < 0)
-               return ret;
-        }
-        if (demix) {
-            ret = write_parameter_block(s, demix);
-            if (ret < 0)
-               return ret;
-        }
-        if (recon) {
-            ret = write_parameter_block(s, recon);
-            if (ret < 0)
-               return ret;
-        }
-    }
-    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);
-    }
-
-    ret = avio_open_dyn_buf(&dyn_bc);
-    if (ret < 0)
-        return ret;
-
-    init_put_bits(&pb, header, sizeof(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);
-    avio_write(s->pb, header, put_bytes_count(&pb, 1));
-
-    if (skip_samples || discard_padding) {
-        ffio_write_leb(dyn_bc, discard_padding);
-        ffio_write_leb(dyn_bc, skip_samples);
-    }
-
-    if (st->id > 17)
-        ffio_write_leb(dyn_bc, st->id);
-
-    dyn_size = avio_get_dyn_buf(dyn_bc, &dyn_buf);
-    ffio_write_leb(s->pb, dyn_size + pkt->size);
-    avio_write(s->pb, dyn_buf, dyn_size);
-    ffio_free_dyn_buf(&dyn_bc);
-    avio_write(s->pb, pkt->data, pkt->size);
-
-    return 0;
+    return ret;
 }
 
 static void iamf_deinit(AVFormatContext *s)
@@ -354,8 +153,6 @@ static void iamf_deinit(AVFormatContext *s)
     IAMFContext *const iamf = &c->iamf;
 
     ff_iamf_uninit_context(iamf);
-
-    return;
 }
 
 static const AVCodecTag iamf_codec_tags[] = {