diff --git a/fftools/ffmpeg.h b/fftools/ffmpeg.h
index 41935d39d5..057535adbb 100644
--- a/fftools/ffmpeg.h
+++ b/fftools/ffmpeg.h
@@ -262,6 +262,8 @@ typedef struct OptionsContext {
     int        nb_disposition;
     SpecifierOpt *program;
     int        nb_program;
+    SpecifierOpt *stream_groups;
+    int        nb_stream_groups;
     SpecifierOpt *time_bases;
     int        nb_time_bases;
     SpecifierOpt *enc_time_bases;
diff --git a/fftools/ffmpeg_mux_init.c b/fftools/ffmpeg_mux_init.c
index 63a25a350f..7648f2a2f1 100644
--- a/fftools/ffmpeg_mux_init.c
+++ b/fftools/ffmpeg_mux_init.c
@@ -39,6 +39,7 @@
 #include "libavutil/dict.h"
 #include "libavutil/display.h"
 #include "libavutil/getenv_utf8.h"
+#include "libavutil/iamf.h"
 #include "libavutil/intreadwrite.h"
 #include "libavutil/log.h"
 #include "libavutil/mem.h"
@@ -1943,6 +1944,336 @@ static int setup_sync_queues(Muxer *mux, AVFormatContext *oc, int64_t buf_size_u
     return 0;
 }
 
+static int of_parse_iamf_audio_element_layers(Muxer *mux, AVStreamGroup *stg, char **ptr)
+{
+    AVIAMFAudioElement *audio_element = stg->params.iamf_audio_element;
+    AVDictionary *dict = NULL;
+    const char *token;
+    int ret = 0;
+
+    audio_element->demixing_info =
+        av_iamf_param_definition_alloc(AV_IAMF_PARAMETER_DEFINITION_DEMIXING, 1, NULL);
+    audio_element->recon_gain_info =
+        av_iamf_param_definition_alloc(AV_IAMF_PARAMETER_DEFINITION_RECON_GAIN, 1, NULL);
+
+    if (!audio_element->demixing_info ||
+        !audio_element->recon_gain_info)
+        return AVERROR(ENOMEM);
+
+    /* process manually set layers and parameters */
+    token = av_strtok(NULL, ",", ptr);
+    while (token) {
+        const AVDictionaryEntry *e;
+        int demixing = 0, recon_gain = 0;
+        int layer = 0;
+
+        if (av_strstart(token, "layer=", &token))
+            layer = 1;
+        else if (av_strstart(token, "demixing=", &token))
+            demixing = 1;
+        else if (av_strstart(token, "recon_gain=", &token))
+            recon_gain = 1;
+
+        av_dict_free(&dict);
+        ret = av_dict_parse_string(&dict, token, "=", ":", 0);
+        if (ret < 0) {
+            av_log(mux, AV_LOG_ERROR, "Error parsing audio element specification %s\n", token);
+            goto fail;
+        }
+
+        if (layer) {
+            AVIAMFLayer *audio_layer = av_iamf_audio_element_add_layer(audio_element);
+            if (!audio_layer) {
+                av_log(mux, AV_LOG_ERROR, "Error adding layer to stream group %d\n", stg->index);
+                ret = AVERROR(ENOMEM);
+                goto fail;
+            }
+            av_opt_set_dict(audio_layer, &dict);
+        } else if (demixing || recon_gain) {
+            AVIAMFParamDefinition *param = demixing ? audio_element->demixing_info
+                                                    : audio_element->recon_gain_info;
+            void *subblock = av_iamf_param_definition_get_subblock(param, 0);
+
+            av_opt_set_dict(param, &dict);
+            av_opt_set_dict(subblock, &dict);
+
+            /* Hardcode spec parameters */
+            param->param_definition_mode = 0;
+            param->parameter_rate = stg->streams[0]->codecpar->sample_rate;
+            param->duration =
+            param->constant_subblock_duration = stg->streams[0]->codecpar->frame_size;
+        }
+
+        // make sure that no entries are left in the dict
+        e = NULL;
+        if (e = av_dict_iterate(dict, e)) {
+            av_log(mux, AV_LOG_FATAL, "Unknown layer key %s.\n", e->key);
+            ret = AVERROR(EINVAL);
+            goto fail;
+        }
+        token = av_strtok(NULL, ",", ptr);
+    }
+
+fail:
+    av_dict_free(&dict);
+    if (!ret && !audio_element->nb_layers) {
+        av_log(mux, AV_LOG_ERROR, "No layer in audio element specification\n");
+        ret = AVERROR(EINVAL);
+    }
+
+    return ret;
+}
+
+static int of_parse_iamf_submixes(Muxer *mux, AVStreamGroup *stg, char **ptr)
+{
+    AVFormatContext *oc = mux->fc;
+    AVIAMFMixPresentation *mix = stg->params.iamf_mix_presentation;
+    AVDictionary *dict = NULL;
+    const char *token;
+    char *submix_str = NULL;
+    int ret = 0;
+
+    /* process manually set submixes */
+    token = av_strtok(NULL, ",", ptr);
+    while (token) {
+        AVIAMFSubmix *submix = NULL;
+        const char *subtoken;
+        char *subptr = NULL;
+
+        if (!av_strstart(token, "submix=", &token)) {
+            av_log(mux, AV_LOG_ERROR, "No submix in mix presentation specification \"%s\"\n", token);
+            goto fail;
+        }
+
+        submix_str = av_strdup(token);
+        if (!submix_str)
+            goto fail;
+
+        submix = av_iamf_mix_presentation_add_submix(mix);
+        if (!submix) {
+            av_log(mux, AV_LOG_ERROR, "Error adding submix to stream group %d\n", stg->index);
+            ret = AVERROR(ENOMEM);
+            goto fail;
+        }
+        submix->output_mix_config =
+            av_iamf_param_definition_alloc(AV_IAMF_PARAMETER_DEFINITION_MIX_GAIN, 0, NULL);
+        if (!submix->output_mix_config) {
+            ret = AVERROR(ENOMEM);
+            goto fail;
+        }
+
+        submix->output_mix_config->parameter_rate = stg->streams[0]->codecpar->sample_rate;
+
+        subptr = NULL;
+        subtoken = av_strtok(submix_str, "|", &subptr);
+        while (subtoken) {
+            const AVDictionaryEntry *e;
+            int element = 0, layout = 0;
+
+            if (av_strstart(subtoken, "element=", &subtoken))
+                element = 1;
+            else if (av_strstart(subtoken, "layout=", &subtoken))
+                layout = 1;
+
+            av_dict_free(&dict);
+            ret = av_dict_parse_string(&dict, subtoken, "=", ":", 0);
+            if (ret < 0) {
+                av_log(mux, AV_LOG_ERROR, "Error parsing submix specification \"%s\"\n", subtoken);
+                goto fail;
+            }
+
+            if (element) {
+                AVIAMFSubmixElement *submix_element;
+                int idx = -1;
+
+                if (e = av_dict_get(dict, "stg", NULL, 0))
+                    idx = strtol(e->value, NULL, 0);
+                av_dict_set(&dict, "stg", NULL, 0);
+                if (idx < 0 || idx >= oc->nb_stream_groups) {
+                    av_log(mux, AV_LOG_ERROR, "Invalid or missing stream group index in "
+                                              "submix element specification \"%s\"\n", subtoken);
+                    ret = AVERROR(EINVAL);
+                    goto fail;
+                }
+                submix_element = av_iamf_submix_add_element(submix);
+                if (!submix_element) {
+                    av_log(mux, AV_LOG_ERROR, "Error adding element to submix\n");
+                    ret = AVERROR(ENOMEM);
+                    goto fail;
+                }
+
+                submix_element->audio_element_id = oc->stream_groups[idx]->id;
+
+                submix_element->element_mix_config =
+                    av_iamf_param_definition_alloc(AV_IAMF_PARAMETER_DEFINITION_MIX_GAIN, 0, NULL);
+                if (!submix_element->element_mix_config)
+                    ret = AVERROR(ENOMEM);
+                av_opt_set_dict2(submix_element, &dict, AV_OPT_SEARCH_CHILDREN);
+                submix_element->element_mix_config->parameter_rate = stg->streams[0]->codecpar->sample_rate;
+            } else if (layout) {
+                AVIAMFSubmixLayout *submix_layout = av_iamf_submix_add_layout(submix);
+                if (!submix_layout) {
+                    av_log(mux, AV_LOG_ERROR, "Error adding layout to submix\n");
+                    ret = AVERROR(ENOMEM);
+                    goto fail;
+                }
+                av_opt_set_dict(submix_layout, &dict);
+            } else
+                av_opt_set_dict2(submix, &dict, AV_OPT_SEARCH_CHILDREN);
+
+            if (ret < 0) {
+                goto fail;
+            }
+
+            // make sure that no entries are left in the dict
+            e = NULL;
+            while (e = av_dict_iterate(dict, e)) {
+                av_log(mux, AV_LOG_FATAL, "Unknown submix key %s.\n", e->key);
+                ret = AVERROR(EINVAL);
+                goto fail;
+            }
+            subtoken = av_strtok(NULL, "|", &subptr);
+        }
+        av_freep(&submix_str);
+
+        if (!submix->nb_elements) {
+            av_log(mux, AV_LOG_ERROR, "No audio elements in submix specification \"%s\"\n", token);
+            ret = AVERROR(EINVAL);
+        }
+        token = av_strtok(NULL, ",", ptr);
+    }
+
+fail:
+    av_dict_free(&dict);
+    av_free(submix_str);
+
+    return ret;
+}
+
+static int of_add_groups(Muxer *mux, const OptionsContext *o)
+{
+    AVFormatContext *oc = mux->fc;
+    int ret;
+
+    /* process manually set groups */
+    for (int i = 0; i < o->nb_stream_groups; i++) {
+        AVDictionary *dict = NULL, *tmp = NULL;
+        const AVDictionaryEntry *e;
+        AVStreamGroup *stg = NULL;
+        int type;
+        const char *token;
+        char *str, *ptr = NULL;
+        const AVOption opts[] = {
+            { "type", "Set group type", offsetof(AVStreamGroup, type), AV_OPT_TYPE_INT,
+                    { .i64 = 0 }, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "type" },
+                { "iamf_audio_element",    NULL, 0, AV_OPT_TYPE_CONST,
+                    { .i64 = AV_STREAM_GROUP_PARAMS_IAMF_AUDIO_ELEMENT },    .unit = "type" },
+                { "iamf_mix_presentation", NULL, 0, AV_OPT_TYPE_CONST,
+                    { .i64 = AV_STREAM_GROUP_PARAMS_IAMF_MIX_PRESENTATION }, .unit = "type" },
+            { NULL },
+        };
+         const AVClass class = {
+            .class_name = "StreamGroupType",
+            .item_name  = av_default_item_name,
+            .option     = opts,
+            .version    = LIBAVUTIL_VERSION_INT,
+        };
+        const AVClass *pclass = &class;
+
+        str = av_strdup(o->stream_groups[i].u.str);
+        if (!str)
+            goto end;
+
+        token = av_strtok(str, ",", &ptr);
+        if (token) {
+            ret = av_dict_parse_string(&dict, token, "=", ":", AV_DICT_MULTIKEY);
+            if (ret < 0) {
+                av_log(mux, AV_LOG_ERROR, "Error parsing group specification %s\n", token);
+                goto end;
+            }
+
+            // "type" is not a user settable option in AVStreamGroup
+            e = av_dict_get(dict, "type", NULL, 0);
+            if (!e) {
+                av_log(mux, AV_LOG_ERROR, "No type define for Steam Group %d\n", i);
+                ret = AVERROR(EINVAL);
+                goto end;
+            }
+
+            ret = av_opt_eval_int(&pclass, opts, e->value, &type);
+            if (ret < 0 || type == AV_STREAM_GROUP_PARAMS_NONE) {
+                av_log(mux, AV_LOG_ERROR, "Invalid group type \"%s\"\n", e->value);
+                goto end;
+            }
+
+            av_dict_copy(&tmp, dict, 0);
+            stg = avformat_stream_group_create(oc, type, &tmp);
+            if (!stg) {
+                ret = AVERROR(ENOMEM);
+                goto end;
+            }
+            av_dict_set(&tmp, "type", NULL, 0);
+
+            e = NULL;
+            while (e = av_dict_get(dict, "st", e, 0)) {
+                unsigned int idx = strtol(e->value, NULL, 0);
+                if (idx >= oc->nb_streams) {
+                    av_log(mux, AV_LOG_ERROR, "Invalid stream index %d\n", idx);
+                    ret = AVERROR(EINVAL);
+                    goto end;
+                }
+                avformat_stream_group_add_stream(stg, oc->streams[idx]);
+            }
+            while (e = av_dict_get(dict, "stg", e, 0)) {
+                unsigned int idx = strtol(e->value, NULL, 0);
+                if (idx >= oc->nb_stream_groups || idx == stg->index) {
+                    av_log(mux, AV_LOG_ERROR, "Invalid stream group index %d\n", idx);
+                    ret = AVERROR(EINVAL);
+                    goto end;
+                }
+                for (int j = 0; j < oc->stream_groups[idx]->nb_streams; j++)
+                    avformat_stream_group_add_stream(stg, oc->stream_groups[idx]->streams[j]);
+            }
+
+            switch(type) {
+            case AV_STREAM_GROUP_PARAMS_IAMF_AUDIO_ELEMENT:
+                ret = of_parse_iamf_audio_element_layers(mux, stg, &ptr);
+                break;
+            case AV_STREAM_GROUP_PARAMS_IAMF_MIX_PRESENTATION:
+                ret = of_parse_iamf_submixes(mux, stg, &ptr);
+                break;
+            default:
+                av_log(mux, AV_LOG_FATAL, "Unknown group type %d.\n", type);
+                ret = AVERROR(EINVAL);
+                break;
+            }
+
+            if (ret < 0)
+                goto end;
+
+            // make sure that nothing but "st" and "stg" entries are left in the dict
+            e = NULL;
+            while (e = av_dict_iterate(tmp, e)) {
+                if (!strcmp(e->key, "st") || !strcmp(e->key, "stg"))
+                    continue;
+
+                av_log(mux, AV_LOG_FATAL, "Unknown group key %s.\n", e->key);
+                ret = AVERROR(EINVAL);
+                goto end;
+            }
+        }
+
+end:
+        av_dict_free(&dict);
+        av_dict_free(&tmp);
+        av_free(str);
+        if (ret < 0)
+            return ret;
+    }
+
+    return 0;
+}
+
 static int of_add_programs(Muxer *mux, const OptionsContext *o)
 {
     AVFormatContext *oc = mux->fc;
@@ -2740,6 +3071,10 @@ int of_open(const OptionsContext *o, const char *filename)
     if (err < 0)
         return err;
 
+    err = of_add_groups(mux, o);
+    if (err < 0)
+        return err;
+
     err = of_add_programs(mux, o);
     if (err < 0)
         return err;
diff --git a/fftools/ffmpeg_opt.c b/fftools/ffmpeg_opt.c
index 304471dd03..1144f64f89 100644
--- a/fftools/ffmpeg_opt.c
+++ b/fftools/ffmpeg_opt.c
@@ -1491,6 +1491,8 @@ const OptionDef options[] = {
         "add metadata", "string=string" },
     { "program",        HAS_ARG | OPT_STRING | OPT_SPEC | OPT_OUTPUT, { .off = OFFSET(program) },
         "add program with specified streams", "title=string:st=number..." },
+    { "stream_group",        HAS_ARG | OPT_STRING | OPT_SPEC | OPT_OUTPUT, { .off = OFFSET(stream_groups) },
+        "add stream group with specified streams and group type-specific arguments", "id=number:st=number..." },
     { "dframes",        HAS_ARG | OPT_PERFILE | OPT_EXPERT |
                         OPT_OUTPUT,                                  { .func_arg = opt_data_frames },
         "set the number of data frames to output", "number" },
