avconv: only apply presets when we have an encoder.

Fixes a crash when using a preset with stream copy.

CC: libav-stable@libav.org

avconv_opt.c

@@ -754,8 +754,6 @@ static OutputStream *new_output_stream(OptionsContext *o, AVFormatContext *oc, e
     char *bsf = NULL, *next, *codec_tag = NULL;
     AVBitStreamFilterContext *bsfc, *bsfc_prev = NULL;
     double qscale = -1;
-    char *buf = NULL, *arg = NULL, *preset = NULL;
-    AVIOContext *s = NULL;
 
     if (!st) {
         av_log(NULL, AV_LOG_FATAL, "Could not alloc stream.\n");
@@ -777,37 +775,40 @@ static OutputStream *new_output_stream(OptionsContext *o, AVFormatContext *oc, e
     st->codec->codec_type = type;
     choose_encoder(o, oc, ost);
     if (ost->enc) {
+        AVIOContext *s = NULL;
+        char *buf = NULL, *arg = NULL, *preset = NULL;
+
         ost->opts  = filter_codec_opts(codec_opts, ost->enc->id, oc, st, ost->enc);
+
+        MATCH_PER_STREAM_OPT(presets, str, preset, oc, st);
+        if (preset && (!(ret = get_preset_file_2(preset, ost->enc->name, &s)))) {
+            do  {
+                buf = get_line(s);
+                if (!buf[0] || buf[0] == '#') {
+                    av_free(buf);
+                    continue;
+                }
+                if (!(arg = strchr(buf, '='))) {
+                    av_log(NULL, AV_LOG_FATAL, "Invalid line found in the preset file.\n");
+                    exit(1);
+                }
+                *arg++ = 0;
+                av_dict_set(&ost->opts, buf, arg, AV_DICT_DONT_OVERWRITE);
+                av_free(buf);
+            } while (!s->eof_reached);
+            avio_close(s);
+        }
+        if (ret) {
+            av_log(NULL, AV_LOG_FATAL,
+                   "Preset %s specified for stream %d:%d, but could not be opened.\n",
+                   preset, ost->file_index, ost->index);
+            exit(1);
+        }
     }
 
     avcodec_get_context_defaults3(st->codec, ost->enc);
     st->codec->codec_type = type; // XXX hack, avcodec_get_context_defaults2() sets type to unknown for stream copy
 
-    MATCH_PER_STREAM_OPT(presets, str, preset, oc, st);
-    if (preset && (!(ret = get_preset_file_2(preset, ost->enc->name, &s)))) {
-        do  {
-            buf = get_line(s);
-            if (!buf[0] || buf[0] == '#') {
-                av_free(buf);
-                continue;
-            }
-            if (!(arg = strchr(buf, '='))) {
-                av_log(NULL, AV_LOG_FATAL, "Invalid line found in the preset file.\n");
-                exit(1);
-            }
-            *arg++ = 0;
-            av_dict_set(&ost->opts, buf, arg, AV_DICT_DONT_OVERWRITE);
-            av_free(buf);
-        } while (!s->eof_reached);
-        avio_close(s);
-    }
-    if (ret) {
-        av_log(NULL, AV_LOG_FATAL,
-               "Preset %s specified for stream %d:%d, but could not be opened.\n",
-               preset, ost->file_index, ost->index);
-        exit(1);
-    }
-
     ost->max_frames = INT64_MAX;
     MATCH_PER_STREAM_OPT(max_frames, i64, ost->max_frames, oc, st);