diff --git a/fftools/ffmpeg.c b/fftools/ffmpeg.c
index 84ace5d414..a7e856e9e2 100644
--- a/fftools/ffmpeg.c
+++ b/fftools/ffmpeg.c
@@ -1768,7 +1768,7 @@ static int process_input_packet(InputStream *ist, const AVPacket *pkt, int no_eo
             continue;
         }
 
-        of_streamcopy(ist, ost, pkt, ist->dts);
+        of_streamcopy(ost, pkt, ist->dts);
     }
 
     return !eof_reached;
diff --git a/fftools/ffmpeg.h b/fftools/ffmpeg.h
index 46b4614ec4..6ad3245166 100644
--- a/fftools/ffmpeg.h
+++ b/fftools/ffmpeg.h
@@ -876,8 +876,7 @@ void of_output_packet(OutputFile *of, AVPacket *pkt, OutputStream *ost, int eof)
 /**
  * @param dts predicted packet dts in AV_TIME_BASE_Q
  */
-void of_streamcopy(InputStream *ist, OutputStream *ost,
-                   const AVPacket *pkt, int64_t dts);
+void of_streamcopy(OutputStream *ost, const AVPacket *pkt, int64_t dts);
 
 int64_t of_filesize(OutputFile *of);
 
diff --git a/fftools/ffmpeg_mux.c b/fftools/ffmpeg_mux.c
index db6ad9d589..8c710c2eac 100644
--- a/fftools/ffmpeg_mux.c
+++ b/fftools/ffmpeg_mux.c
@@ -378,10 +378,10 @@ fail:
 
 }
 
-void of_streamcopy(InputStream *ist, OutputStream *ost,
-                   const AVPacket *pkt, int64_t dts)
+void of_streamcopy(OutputStream *ost, const AVPacket *pkt, int64_t dts)
 {
     OutputFile *of = output_files[ost->file_index];
+    MuxStream  *ms = ms_from_ost(ost);
     int64_t start_time = (of->start_time == AV_NOPTS_VALUE) ? 0 : of->start_time;
     int64_t ost_tb_start_time = av_rescale_q(start_time, AV_TIME_BASE_Q, ost->mux_timebase);
     AVPacket *opkt = ost->pkt;
@@ -430,7 +430,7 @@ void of_streamcopy(InputStream *ist, OutputStream *ost,
             duration = ost->par_in->frame_size;
         opkt->dts = av_rescale_delta(pkt->time_base, pkt->dts,
                                     (AVRational){1, ost->par_in->sample_rate}, duration,
-                                    &ist->filter_in_rescale_delta_last, opkt->time_base);
+                                    &ms->ts_rescale_delta_last, opkt->time_base);
         /* dts will be set immediately afterwards to what pts is now */
         opkt->pts = opkt->dts - ost_tb_start_time;
     } else
diff --git a/fftools/ffmpeg_mux.h b/fftools/ffmpeg_mux.h
index 3fab74b2ed..e8c4ea4847 100644
--- a/fftools/ffmpeg_mux.h
+++ b/fftools/ffmpeg_mux.h
@@ -64,6 +64,9 @@ typedef struct MuxStream {
      * used for making up missing dts values */
     int64_t last_mux_dts;
 
+    // audio streamcopy - state for av_rescale_delta()
+    int64_t ts_rescale_delta_last;
+
     // combined size of all the packets sent to the muxer
     uint64_t data_size_mux;
 } MuxStream;