diff --git a/ffmpeg.c b/ffmpeg.c
index ab0093edf0..83c51aa675 100644
--- a/ffmpeg.c
+++ b/ffmpeg.c
@@ -587,7 +587,7 @@ static void close_all_output_streams(OutputStream *ost, OSTFinished this_stream,
 static void write_frame(AVFormatContext *s, AVPacket *pkt, OutputStream *ost)
 {
     AVBitStreamFilterContext *bsfc = ost->bitstream_filters;
-    AVCodecContext          *avctx = ost->st->codec;
+    AVCodecContext          *avctx = ost->encoding_needed ? ost->enc_ctx : ost->st->codec;
     int ret;
 
     if (!ost->st->codec->extradata_size && ost->enc_ctx->extradata_size) {
@@ -2513,7 +2513,7 @@ static int transcode_init(void)
         if (ost->attachment_filename)
             continue;
 
-        enc_ctx = ost->enc_ctx;
+        enc_ctx = ost->stream_copy ? ost->st->codec : ost->enc_ctx;
 
         if (ist) {
             dec_ctx = ist->dec_ctx;
@@ -2881,24 +2881,26 @@ static int transcode_init(void)
             if (ost->enc_ctx->bit_rate && ost->enc_ctx->bit_rate < 1000)
                 av_log(NULL, AV_LOG_WARNING, "The bitrate parameter is set too low."
                                              " It takes bits/s as argument, not kbits/s\n");
+
+            ret = avcodec_copy_context(ost->st->codec, ost->enc_ctx);
+            if (ret < 0) {
+                av_log(NULL, AV_LOG_FATAL,
+                       "Error initializing the output stream codec context.\n");
+                exit_program(1);
+            }
+
+            // copy timebase while removing common factors
+            ost->st->time_base = av_add_q(ost->enc_ctx->time_base, (AVRational){0, 1});
+            ost->st->codec->codec= ost->enc_ctx->codec;
         } else {
             if (av_opt_set_dict(ost->enc_ctx, &ost->encoder_opts) < 0) {
                 av_log(NULL, AV_LOG_FATAL,
                     "Error setting up codec context options.\n");
                 exit_program(1);
             }
+            // copy timebase while removing common factors
+            ost->st->time_base = av_add_q(ost->st->codec->time_base, (AVRational){0, 1});
         }
-
-        ret = avcodec_copy_context(ost->st->codec, ost->enc_ctx);
-        if (ret < 0) {
-            av_log(NULL, AV_LOG_FATAL,
-                   "Error initializing the output stream codec context.\n");
-            exit_program(1);
-        }
-        ost->st->codec->codec= ost->enc_ctx->codec;
-
-        // copy timebase while removing common factors
-        ost->st->time_base = av_add_q(ost->enc_ctx->time_base, (AVRational){0, 1});
     }
 
     /* init input streams */
diff --git a/ffmpeg_opt.c b/ffmpeg_opt.c
index 0c7b35a269..239a030031 100644
--- a/ffmpeg_opt.c
+++ b/ffmpeg_opt.c
@@ -1977,8 +1977,8 @@ loop_end:
         ost->stream_copy               = 0;
         ost->attachment_filename       = o->attachments[i];
         ost->finished                  = 1;
-        ost->enc_ctx->extradata      = attachment;
-        ost->enc_ctx->extradata_size = len;
+        ost->st->codec->extradata      = attachment;
+        ost->st->codec->extradata_size = len;
 
         p = strrchr(o->attachments[i], '/');
         av_dict_set(&ost->st->metadata, "filename", (p && *p) ? p + 1 : o->attachments[i], AV_DICT_DONT_OVERWRITE);