diff --git a/fftools/Makefile b/fftools/Makefile
index da420786eb..27a22250b3 100644
--- a/fftools/Makefile
+++ b/fftools/Makefile
@@ -9,7 +9,11 @@ AVBASENAMES  = ffmpeg ffplay ffprobe
 ALLAVPROGS   = $(AVBASENAMES:%=%$(PROGSSUF)$(EXESUF))
 ALLAVPROGS_G = $(AVBASENAMES:%=%$(PROGSSUF)_g$(EXESUF))
 
-OBJS-ffmpeg                        += fftools/ffmpeg_opt.o fftools/ffmpeg_filter.o fftools/ffmpeg_hw.o
+OBJS-ffmpeg +=                  \
+    fftools/ffmpeg_filter.o     \
+    fftools/ffmpeg_hw.o         \
+    fftools/ffmpeg_mux.o        \
+    fftools/ffmpeg_opt.o        \
 
 define DOFFTOOL
 OBJS-$(1) += fftools/cmdutils.o fftools/$(1).o $(OBJS-$(1)-yes)
diff --git a/fftools/ffmpeg.c b/fftools/ffmpeg.c
index 1961653dcc..e0aa533dc9 100644
--- a/fftools/ffmpeg.c
+++ b/fftools/ffmpeg.c
@@ -136,9 +136,9 @@ static int nb_frames_dup = 0;
 static unsigned dup_warning = 1000;
 static int nb_frames_drop = 0;
 static int64_t decode_error_stat[2];
-static unsigned nb_output_dumped = 0;
+unsigned nb_output_dumped = 0;
 
-static int want_sdp = 1;
+int want_sdp = 1;
 
 static BenchmarkTimeStamps current_time;
 AVIOContext *progress_avio = NULL;
@@ -344,7 +344,7 @@ static volatile int received_sigterm = 0;
 static volatile int received_nb_signals = 0;
 static atomic_int transcode_init_done = ATOMIC_VAR_INIT(0);
 static volatile int ffmpeg_exited = 0;
-static int main_return_code = 0;
+int main_return_code = 0;
 static int64_t copy_ts_first_pts = AV_NOPTS_VALUE;
 
 static void
@@ -715,159 +715,6 @@ static void update_benchmark(const char *fmt, ...)
     }
 }
 
-static void close_all_output_streams(OutputStream *ost, OSTFinished this_stream, OSTFinished others)
-{
-    int i;
-    for (i = 0; i < nb_output_streams; i++) {
-        OutputStream *ost2 = output_streams[i];
-        ost2->finished |= ost == ost2 ? this_stream : others;
-    }
-}
-
-static void write_packet(OutputFile *of, AVPacket *pkt, OutputStream *ost, int unqueue)
-{
-    AVFormatContext *s = of->ctx;
-    AVStream *st = ost->st;
-    int ret;
-
-    /*
-     * Audio encoders may split the packets --  #frames in != #packets out.
-     * But there is no reordering, so we can limit the number of output packets
-     * by simply dropping them here.
-     * Counting encoded video frames needs to be done separately because of
-     * reordering, see do_video_out().
-     * Do not count the packet when unqueued because it has been counted when queued.
-     */
-    if (!(st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO && ost->encoding_needed) && !unqueue) {
-        if (ost->frame_number >= ost->max_frames) {
-            av_packet_unref(pkt);
-            return;
-        }
-        ost->frame_number++;
-    }
-
-    if (!of->header_written) {
-        AVPacket *tmp_pkt;
-        /* the muxer is not initialized yet, buffer the packet */
-        if (!av_fifo_space(ost->muxing_queue)) {
-            size_t cur_size = av_fifo_size(ost->muxing_queue);
-            unsigned int are_we_over_size =
-                (ost->muxing_queue_data_size + pkt->size) > ost->muxing_queue_data_threshold;
-            size_t limit    = are_we_over_size ? ost->max_muxing_queue_size : INT_MAX;
-            size_t new_size = FFMIN(2 * cur_size, limit);
-
-            if (new_size <= cur_size) {
-                av_log(NULL, AV_LOG_ERROR,
-                       "Too many packets buffered for output stream %d:%d.\n",
-                       ost->file_index, ost->st->index);
-                exit_program(1);
-            }
-            ret = av_fifo_realloc2(ost->muxing_queue, new_size);
-            if (ret < 0)
-                exit_program(1);
-        }
-        ret = av_packet_make_refcounted(pkt);
-        if (ret < 0)
-            exit_program(1);
-        tmp_pkt = av_packet_alloc();
-        if (!tmp_pkt)
-            exit_program(1);
-        av_packet_move_ref(tmp_pkt, pkt);
-        ost->muxing_queue_data_size += tmp_pkt->size;
-        av_fifo_generic_write(ost->muxing_queue, &tmp_pkt, sizeof(tmp_pkt), NULL);
-        return;
-    }
-
-    if ((st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO && video_sync_method == VSYNC_DROP) ||
-        (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO && audio_sync_method < 0))
-        pkt->pts = pkt->dts = AV_NOPTS_VALUE;
-
-    if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
-        int i;
-        uint8_t *sd = av_packet_get_side_data(pkt, AV_PKT_DATA_QUALITY_STATS,
-                                              NULL);
-        ost->quality = sd ? AV_RL32(sd) : -1;
-        ost->pict_type = sd ? sd[4] : AV_PICTURE_TYPE_NONE;
-
-        for (i = 0; i<FF_ARRAY_ELEMS(ost->error); i++) {
-            if (sd && i < sd[5])
-                ost->error[i] = AV_RL64(sd + 8 + 8*i);
-            else
-                ost->error[i] = -1;
-        }
-
-        if (ost->frame_rate.num && ost->is_cfr) {
-            if (pkt->duration > 0)
-                av_log(NULL, AV_LOG_WARNING, "Overriding packet duration by frame rate, this should not happen\n");
-            pkt->duration = av_rescale_q(1, av_inv_q(ost->frame_rate),
-                                         ost->mux_timebase);
-        }
-    }
-
-    av_packet_rescale_ts(pkt, ost->mux_timebase, ost->st->time_base);
-
-    if (!(s->oformat->flags & AVFMT_NOTIMESTAMPS)) {
-        if (pkt->dts != AV_NOPTS_VALUE &&
-            pkt->pts != AV_NOPTS_VALUE &&
-            pkt->dts > pkt->pts) {
-            av_log(s, AV_LOG_WARNING, "Invalid DTS: %"PRId64" PTS: %"PRId64" in output stream %d:%d, replacing by guess\n",
-                   pkt->dts, pkt->pts,
-                   ost->file_index, ost->st->index);
-            pkt->pts =
-            pkt->dts = pkt->pts + pkt->dts + ost->last_mux_dts + 1
-                     - FFMIN3(pkt->pts, pkt->dts, ost->last_mux_dts + 1)
-                     - FFMAX3(pkt->pts, pkt->dts, ost->last_mux_dts + 1);
-        }
-        if ((st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO || st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO || st->codecpar->codec_type == AVMEDIA_TYPE_SUBTITLE) &&
-            pkt->dts != AV_NOPTS_VALUE &&
-            !(st->codecpar->codec_id == AV_CODEC_ID_VP9 && ost->stream_copy) &&
-            ost->last_mux_dts != AV_NOPTS_VALUE) {
-            int64_t max = ost->last_mux_dts + !(s->oformat->flags & AVFMT_TS_NONSTRICT);
-            if (pkt->dts < max) {
-                int loglevel = max - pkt->dts > 2 || st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO ? AV_LOG_WARNING : AV_LOG_DEBUG;
-                if (exit_on_error)
-                    loglevel = AV_LOG_ERROR;
-                av_log(s, loglevel, "Non-monotonous DTS in output stream "
-                       "%d:%d; previous: %"PRId64", current: %"PRId64"; ",
-                       ost->file_index, ost->st->index, ost->last_mux_dts, pkt->dts);
-                if (exit_on_error) {
-                    av_log(NULL, AV_LOG_FATAL, "aborting.\n");
-                    exit_program(1);
-                }
-                av_log(s, loglevel, "changing to %"PRId64". This may result "
-                       "in incorrect timestamps in the output file.\n",
-                       max);
-                if (pkt->pts >= pkt->dts)
-                    pkt->pts = FFMAX(pkt->pts, max);
-                pkt->dts = max;
-            }
-        }
-    }
-    ost->last_mux_dts = pkt->dts;
-
-    ost->data_size += pkt->size;
-    ost->packets_written++;
-
-    pkt->stream_index = ost->index;
-
-    if (debug_ts) {
-        av_log(NULL, AV_LOG_INFO, "muxer <- type:%s "
-                "pkt_pts:%s pkt_pts_time:%s pkt_dts:%s pkt_dts_time:%s size:%d\n",
-                av_get_media_type_string(ost->enc_ctx->codec_type),
-                av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, &ost->st->time_base),
-                av_ts2str(pkt->dts), av_ts2timestr(pkt->dts, &ost->st->time_base),
-                pkt->size
-              );
-    }
-
-    ret = av_interleaved_write_frame(s, pkt);
-    if (ret < 0) {
-        print_error("av_interleaved_write_frame()", ret);
-        main_return_code = 1;
-        close_all_output_streams(ost, MUXER_FINISHED | ENCODER_FINISHED, ENCODER_FINISHED);
-    }
-}
-
 static void close_output_stream(OutputStream *ost)
 {
     OutputFile *of = output_files[ost->file_index];
@@ -902,11 +749,11 @@ static void output_packet(OutputFile *of, AVPacket *pkt,
         if (ret < 0)
             goto finish;
         while ((ret = av_bsf_receive_packet(ost->bsf_ctx, pkt)) >= 0)
-            write_packet(of, pkt, ost, 0);
+            of_write_packet(of, pkt, ost, 0);
         if (ret == AVERROR(EAGAIN))
             ret = 0;
     } else if (!eof)
-        write_packet(of, pkt, ost, 0);
+        of_write_packet(of, pkt, ost, 0);
 
 finish:
     if (ret < 0 && ret != AVERROR_EOF) {
@@ -2761,59 +2608,6 @@ static int process_input_packet(InputStream *ist, const AVPacket *pkt, int no_eo
     return !eof_reached;
 }
 
-static int print_sdp(void)
-{
-    char sdp[16384];
-    int i;
-    int j, ret;
-    AVIOContext *sdp_pb;
-    AVFormatContext **avc;
-
-    for (i = 0; i < nb_output_files; i++) {
-        if (!output_files[i]->header_written)
-            return 0;
-    }
-
-    avc = av_malloc_array(nb_output_files, sizeof(*avc));
-    if (!avc)
-        exit_program(1);
-    for (i = 0, j = 0; i < nb_output_files; i++) {
-        if (!strcmp(output_files[i]->ctx->oformat->name, "rtp")) {
-            avc[j] = output_files[i]->ctx;
-            j++;
-        }
-    }
-
-    if (!j) {
-        av_log(NULL, AV_LOG_ERROR, "No output streams in the SDP.\n");
-        ret = AVERROR(EINVAL);
-        goto fail;
-    }
-
-    ret = av_sdp_create(avc, j, sdp, sizeof(sdp));
-    if (ret < 0)
-        goto fail;
-
-    if (!sdp_filename) {
-        printf("SDP:\n%s\n", sdp);
-        fflush(stdout);
-    } else {
-        ret = avio_open2(&sdp_pb, sdp_filename, AVIO_FLAG_WRITE, &int_cb, NULL);
-        if (ret < 0) {
-            av_log(NULL, AV_LOG_ERROR, "Failed to open sdp file '%s'\n", sdp_filename);
-            goto fail;
-        }
-
-        avio_print(sdp_pb, sdp);
-        avio_closep(&sdp_pb);
-        av_freep(&sdp_filename);
-    }
-
-fail:
-    av_freep(&avc);
-    return ret;
-}
-
 static enum AVPixelFormat get_format(AVCodecContext *s, const enum AVPixelFormat *pix_fmts)
 {
     InputStream *ist = s->opaque;
@@ -2940,59 +2734,6 @@ static int compare_int64(const void *a, const void *b)
     return FFDIFFSIGN(*(const int64_t *)a, *(const int64_t *)b);
 }
 
-/* open the muxer when all the streams are initialized */
-static int check_init_output_file(OutputFile *of)
-{
-    int ret, i;
-
-    for (i = 0; i < of->ctx->nb_streams; i++) {
-        OutputStream *ost = output_streams[of->ost_index + i];
-        if (!ost->initialized)
-            return 0;
-    }
-
-    ret = avformat_write_header(of->ctx, &of->opts);
-    if (ret < 0) {
-        av_log(NULL, AV_LOG_ERROR,
-               "Could not write header for output file #%d "
-               "(incorrect codec parameters ?): %s\n",
-               of->index, av_err2str(ret));
-        return ret;
-    }
-    //assert_avoptions(of->opts);
-    of->header_written = 1;
-
-    av_dump_format(of->ctx, of->index, of->ctx->url, 1);
-    nb_output_dumped++;
-
-    if (sdp_filename || want_sdp) {
-        ret = print_sdp();
-        if (ret < 0) {
-            av_log(NULL, AV_LOG_ERROR, "Error writing the SDP.\n");
-            return ret;
-        }
-    }
-
-    /* flush the muxing queues */
-    for (i = 0; i < of->ctx->nb_streams; i++) {
-        OutputStream *ost = output_streams[of->ost_index + i];
-
-        /* try to improve muxing time_base (only possible if nothing has been written yet) */
-        if (!av_fifo_size(ost->muxing_queue))
-            ost->mux_timebase = ost->st->time_base;
-
-        while (av_fifo_size(ost->muxing_queue)) {
-            AVPacket *pkt;
-            av_fifo_generic_read(ost->muxing_queue, &pkt, sizeof(pkt), NULL);
-            ost->muxing_queue_data_size -= pkt->size;
-            write_packet(of, pkt, ost, 1);
-            av_packet_free(&pkt);
-        }
-    }
-
-    return 0;
-}
-
 static int init_output_bsfs(OutputStream *ost)
 {
     AVBSFContext *ctx = ost->bsf_ctx;
@@ -3565,7 +3306,7 @@ static int init_output_stream(OutputStream *ost, AVFrame *frame,
 
     ost->initialized = 1;
 
-    ret = check_init_output_file(output_files[ost->file_index]);
+    ret = of_check_init(output_files[ost->file_index]);
     if (ret < 0)
         return ret;
 
@@ -3668,7 +3409,7 @@ static int transcode_init(void)
     for (i = 0; i < nb_output_files; i++) {
         oc = output_files[i]->ctx;
         if (oc->oformat->flags & AVFMT_NOSTREAMS && oc->nb_streams == 0) {
-            ret = check_init_output_file(output_files[i]);
+            ret = of_check_init(output_files[i]);
             if (ret < 0)
                 goto dump_format;
         }
diff --git a/fftools/ffmpeg.h b/fftools/ffmpeg.h
index 5fd5d2606b..fed34b06f8 100644
--- a/fftools/ffmpeg.h
+++ b/fftools/ffmpeg.h
@@ -644,6 +644,10 @@ extern char *qsv_device;
 #endif
 extern HWDevice *filter_hw_device;
 
+extern int want_sdp;
+extern unsigned nb_output_dumped;
+extern int main_return_code;
+
 
 void term_init(void);
 void term_exit(void);
@@ -680,4 +684,10 @@ int hw_device_setup_for_filter(FilterGraph *fg);
 
 int hwaccel_decode_init(AVCodecContext *avctx);
 
+/* open the muxer when all the streams are initialized */
+int of_check_init(OutputFile *of);
+
+void of_write_packet(OutputFile *of, AVPacket *pkt, OutputStream *ost,
+                     int unqueue);
+
 #endif /* FFTOOLS_FFMPEG_H */
diff --git a/fftools/ffmpeg_mux.c b/fftools/ffmpeg_mux.c
new file mode 100644
index 0000000000..3c2980ba90
--- /dev/null
+++ b/fftools/ffmpeg_mux.c
@@ -0,0 +1,293 @@
+/*
+ * 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 <stdio.h>
+#include <string.h>
+
+#include "ffmpeg.h"
+
+#include "libavutil/fifo.h"
+#include "libavutil/intreadwrite.h"
+#include "libavutil/log.h"
+#include "libavutil/mem.h"
+#include "libavutil/timestamp.h"
+
+#include "libavcodec/packet.h"
+
+#include "libavformat/avformat.h"
+#include "libavformat/avio.h"
+
+static void close_all_output_streams(OutputStream *ost, OSTFinished this_stream, OSTFinished others)
+{
+    int i;
+    for (i = 0; i < nb_output_streams; i++) {
+        OutputStream *ost2 = output_streams[i];
+        ost2->finished |= ost == ost2 ? this_stream : others;
+    }
+}
+
+void of_write_packet(OutputFile *of, AVPacket *pkt, OutputStream *ost,
+                     int unqueue)
+{
+    AVFormatContext *s = of->ctx;
+    AVStream *st = ost->st;
+    int ret;
+
+    /*
+     * Audio encoders may split the packets --  #frames in != #packets out.
+     * But there is no reordering, so we can limit the number of output packets
+     * by simply dropping them here.
+     * Counting encoded video frames needs to be done separately because of
+     * reordering, see do_video_out().
+     * Do not count the packet when unqueued because it has been counted when queued.
+     */
+    if (!(st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO && ost->encoding_needed) && !unqueue) {
+        if (ost->frame_number >= ost->max_frames) {
+            av_packet_unref(pkt);
+            return;
+        }
+        ost->frame_number++;
+    }
+
+    if (!of->header_written) {
+        AVPacket *tmp_pkt;
+        /* the muxer is not initialized yet, buffer the packet */
+        if (!av_fifo_space(ost->muxing_queue)) {
+            size_t cur_size = av_fifo_size(ost->muxing_queue);
+            unsigned int are_we_over_size =
+                (ost->muxing_queue_data_size + pkt->size) > ost->muxing_queue_data_threshold;
+            size_t limit    = are_we_over_size ? ost->max_muxing_queue_size : INT_MAX;
+            size_t new_size = FFMIN(2 * cur_size, limit);
+
+            if (new_size <= cur_size) {
+                av_log(NULL, AV_LOG_ERROR,
+                       "Too many packets buffered for output stream %d:%d.\n",
+                       ost->file_index, ost->st->index);
+                exit_program(1);
+            }
+            ret = av_fifo_realloc2(ost->muxing_queue, new_size);
+            if (ret < 0)
+                exit_program(1);
+        }
+        ret = av_packet_make_refcounted(pkt);
+        if (ret < 0)
+            exit_program(1);
+        tmp_pkt = av_packet_alloc();
+        if (!tmp_pkt)
+            exit_program(1);
+        av_packet_move_ref(tmp_pkt, pkt);
+        ost->muxing_queue_data_size += tmp_pkt->size;
+        av_fifo_generic_write(ost->muxing_queue, &tmp_pkt, sizeof(tmp_pkt), NULL);
+        return;
+    }
+
+    if ((st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO && video_sync_method == VSYNC_DROP) ||
+        (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO && audio_sync_method < 0))
+        pkt->pts = pkt->dts = AV_NOPTS_VALUE;
+
+    if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
+        int i;
+        uint8_t *sd = av_packet_get_side_data(pkt, AV_PKT_DATA_QUALITY_STATS,
+                                              NULL);
+        ost->quality = sd ? AV_RL32(sd) : -1;
+        ost->pict_type = sd ? sd[4] : AV_PICTURE_TYPE_NONE;
+
+        for (i = 0; i<FF_ARRAY_ELEMS(ost->error); i++) {
+            if (sd && i < sd[5])
+                ost->error[i] = AV_RL64(sd + 8 + 8*i);
+            else
+                ost->error[i] = -1;
+        }
+
+        if (ost->frame_rate.num && ost->is_cfr) {
+            if (pkt->duration > 0)
+                av_log(NULL, AV_LOG_WARNING, "Overriding packet duration by frame rate, this should not happen\n");
+            pkt->duration = av_rescale_q(1, av_inv_q(ost->frame_rate),
+                                         ost->mux_timebase);
+        }
+    }
+
+    av_packet_rescale_ts(pkt, ost->mux_timebase, ost->st->time_base);
+
+    if (!(s->oformat->flags & AVFMT_NOTIMESTAMPS)) {
+        if (pkt->dts != AV_NOPTS_VALUE &&
+            pkt->pts != AV_NOPTS_VALUE &&
+            pkt->dts > pkt->pts) {
+            av_log(s, AV_LOG_WARNING, "Invalid DTS: %"PRId64" PTS: %"PRId64" in output stream %d:%d, replacing by guess\n",
+                   pkt->dts, pkt->pts,
+                   ost->file_index, ost->st->index);
+            pkt->pts =
+            pkt->dts = pkt->pts + pkt->dts + ost->last_mux_dts + 1
+                     - FFMIN3(pkt->pts, pkt->dts, ost->last_mux_dts + 1)
+                     - FFMAX3(pkt->pts, pkt->dts, ost->last_mux_dts + 1);
+        }
+        if ((st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO || st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO || st->codecpar->codec_type == AVMEDIA_TYPE_SUBTITLE) &&
+            pkt->dts != AV_NOPTS_VALUE &&
+            !(st->codecpar->codec_id == AV_CODEC_ID_VP9 && ost->stream_copy) &&
+            ost->last_mux_dts != AV_NOPTS_VALUE) {
+            int64_t max = ost->last_mux_dts + !(s->oformat->flags & AVFMT_TS_NONSTRICT);
+            if (pkt->dts < max) {
+                int loglevel = max - pkt->dts > 2 || st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO ? AV_LOG_WARNING : AV_LOG_DEBUG;
+                if (exit_on_error)
+                    loglevel = AV_LOG_ERROR;
+                av_log(s, loglevel, "Non-monotonous DTS in output stream "
+                       "%d:%d; previous: %"PRId64", current: %"PRId64"; ",
+                       ost->file_index, ost->st->index, ost->last_mux_dts, pkt->dts);
+                if (exit_on_error) {
+                    av_log(NULL, AV_LOG_FATAL, "aborting.\n");
+                    exit_program(1);
+                }
+                av_log(s, loglevel, "changing to %"PRId64". This may result "
+                       "in incorrect timestamps in the output file.\n",
+                       max);
+                if (pkt->pts >= pkt->dts)
+                    pkt->pts = FFMAX(pkt->pts, max);
+                pkt->dts = max;
+            }
+        }
+    }
+    ost->last_mux_dts = pkt->dts;
+
+    ost->data_size += pkt->size;
+    ost->packets_written++;
+
+    pkt->stream_index = ost->index;
+
+    if (debug_ts) {
+        av_log(NULL, AV_LOG_INFO, "muxer <- type:%s "
+                "pkt_pts:%s pkt_pts_time:%s pkt_dts:%s pkt_dts_time:%s size:%d\n",
+                av_get_media_type_string(ost->enc_ctx->codec_type),
+                av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, &ost->st->time_base),
+                av_ts2str(pkt->dts), av_ts2timestr(pkt->dts, &ost->st->time_base),
+                pkt->size
+              );
+    }
+
+    ret = av_interleaved_write_frame(s, pkt);
+    if (ret < 0) {
+        print_error("av_interleaved_write_frame()", ret);
+        main_return_code = 1;
+        close_all_output_streams(ost, MUXER_FINISHED | ENCODER_FINISHED, ENCODER_FINISHED);
+    }
+}
+
+static int print_sdp(void)
+{
+    char sdp[16384];
+    int i;
+    int j, ret;
+    AVIOContext *sdp_pb;
+    AVFormatContext **avc;
+
+    for (i = 0; i < nb_output_files; i++) {
+        if (!output_files[i]->header_written)
+            return 0;
+    }
+
+    avc = av_malloc_array(nb_output_files, sizeof(*avc));
+    if (!avc)
+        exit_program(1);
+    for (i = 0, j = 0; i < nb_output_files; i++) {
+        if (!strcmp(output_files[i]->ctx->oformat->name, "rtp")) {
+            avc[j] = output_files[i]->ctx;
+            j++;
+        }
+    }
+
+    if (!j) {
+        av_log(NULL, AV_LOG_ERROR, "No output streams in the SDP.\n");
+        ret = AVERROR(EINVAL);
+        goto fail;
+    }
+
+    ret = av_sdp_create(avc, j, sdp, sizeof(sdp));
+    if (ret < 0)
+        goto fail;
+
+    if (!sdp_filename) {
+        printf("SDP:\n%s\n", sdp);
+        fflush(stdout);
+    } else {
+        ret = avio_open2(&sdp_pb, sdp_filename, AVIO_FLAG_WRITE, &int_cb, NULL);
+        if (ret < 0) {
+            av_log(NULL, AV_LOG_ERROR, "Failed to open sdp file '%s'\n", sdp_filename);
+            goto fail;
+        }
+
+        avio_print(sdp_pb, sdp);
+        avio_closep(&sdp_pb);
+        av_freep(&sdp_filename);
+    }
+
+fail:
+    av_freep(&avc);
+    return ret;
+}
+
+/* open the muxer when all the streams are initialized */
+int of_check_init(OutputFile *of)
+{
+    int ret, i;
+
+    for (i = 0; i < of->ctx->nb_streams; i++) {
+        OutputStream *ost = output_streams[of->ost_index + i];
+        if (!ost->initialized)
+            return 0;
+    }
+
+    ret = avformat_write_header(of->ctx, &of->opts);
+    if (ret < 0) {
+        av_log(NULL, AV_LOG_ERROR,
+               "Could not write header for output file #%d "
+               "(incorrect codec parameters ?): %s\n",
+               of->index, av_err2str(ret));
+        return ret;
+    }
+    //assert_avoptions(of->opts);
+    of->header_written = 1;
+
+    av_dump_format(of->ctx, of->index, of->ctx->url, 1);
+    nb_output_dumped++;
+
+    if (sdp_filename || want_sdp) {
+        ret = print_sdp();
+        if (ret < 0) {
+            av_log(NULL, AV_LOG_ERROR, "Error writing the SDP.\n");
+            return ret;
+        }
+    }
+
+    /* flush the muxing queues */
+    for (i = 0; i < of->ctx->nb_streams; i++) {
+        OutputStream *ost = output_streams[of->ost_index + i];
+
+        /* try to improve muxing time_base (only possible if nothing has been written yet) */
+        if (!av_fifo_size(ost->muxing_queue))
+            ost->mux_timebase = ost->st->time_base;
+
+        while (av_fifo_size(ost->muxing_queue)) {
+            AVPacket *pkt;
+            av_fifo_generic_read(ost->muxing_queue, &pkt, sizeof(pkt), NULL);
+            ost->muxing_queue_data_size -= pkt->size;
+            of_write_packet(of, pkt, ost, 1);
+            av_packet_free(&pkt);
+        }
+    }
+
+    return 0;
+}
