ffmpeg: skip disabled streams

Fully discarded streams can't be selected for output or mapped or filtered.
Previously, a few packets from such streams, probably buffered for
stream probing, would get smuggled into output files.
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

fftools/ffmpeg_filter.c

@@ -293,10 +293,17 @@ static void init_input_filter(FilterGraph *fg, AVFilterInOut *in)
             exit_program(1);
         }
         ist = input_streams[input_files[file_idx]->ist_index + st->index];
+        if (ist->user_set_discard == AVDISCARD_ALL) {
+            av_log(NULL, AV_LOG_FATAL, "Stream specifier '%s' in filtergraph description %s "
+                   "matches a disabled input stream.\n", p, fg->graph_desc);
+            exit_program(1);
+        }
     } else {
         /* find the first unused stream of corresponding type */
         for (i = 0; i < nb_input_streams; i++) {
             ist = input_streams[i];
+            if (ist->user_set_discard == AVDISCARD_ALL)
+                continue;
             if (ist->dec_ctx->codec_type == type && ist->discard)
                 break;
         }

fftools/ffmpeg_opt.c

@@ -268,7 +268,7 @@ static int opt_map(void *optctx, const char *opt, const char *arg)
 {
     OptionsContext *o = optctx;
     StreamMap *m = NULL;
-    int i, negative = 0, file_idx;
+    int i, negative = 0, file_idx, disabled = 0;
     int sync_file_idx = -1, sync_stream_idx = 0;
     char *p, *sync;
     char *map;
@@ -303,6 +303,11 @@ static int opt_map(void *optctx, const char *opt, const char *arg)
                                        "match any streams.\n", arg);
             exit_program(1);
         }
+        if (input_streams[input_files[sync_file_idx]->ist_index + sync_stream_idx]->user_set_discard == AVDISCARD_ALL) {
+            av_log(NULL, AV_LOG_FATAL, "Sync stream specification in map %s matches a disabled input "
+                                       "stream.\n", arg);
+            exit_program(1);
+        }
     }
 
 
@@ -339,6 +344,10 @@ static int opt_map(void *optctx, const char *opt, const char *arg)
                 if (check_stream_specifier(input_files[file_idx]->ctx, input_files[file_idx]->ctx->streams[i],
                             *p == ':' ? p + 1 : p) <= 0)
                     continue;
+                if (input_streams[input_files[file_idx]->ist_index + i]->user_set_discard == AVDISCARD_ALL) {
+                    disabled = 1;
+                    continue;
+                }
                 GROW_ARRAY(o->stream_maps, o->nb_stream_maps);
                 m = &o->stream_maps[o->nb_stream_maps - 1];
 
@@ -358,6 +367,10 @@ static int opt_map(void *optctx, const char *opt, const char *arg)
     if (!m) {
         if (allow_unused) {
             av_log(NULL, AV_LOG_VERBOSE, "Stream map '%s' matches no streams; ignoring.\n", arg);
+        } else if (disabled) {
+            av_log(NULL, AV_LOG_FATAL, "Stream map '%s' matches disabled streams.\n"
+                                       "To ignore this, add a trailing '?' to the map.\n", arg);
+            exit_program(1);
         } else {
             av_log(NULL, AV_LOG_FATAL, "Stream map '%s' matches no streams.\n"
                                        "To ignore this, add a trailing '?' to the map.\n", arg);
@@ -437,7 +450,8 @@ static int opt_map_channel(void *optctx, const char *opt, const char *arg)
     /* allow trailing ? to map_channel */
     if (allow_unused = strchr(mapchan, '?'))
         *allow_unused = 0;
-    if (m->channel_idx < 0 || m->channel_idx >= st->codecpar->channels) {
+    if (m->channel_idx < 0 || m->channel_idx >= st->codecpar->channels ||
+        input_streams[input_files[m->file_idx]->ist_index + m->stream_idx]->user_set_discard == AVDISCARD_ALL) {
         if (allow_unused) {
             av_log(NULL, AV_LOG_VERBOSE, "mapchan: invalid audio channel #%d.%d.%d\n",
                     m->file_idx, m->stream_idx, m->channel_idx);
@@ -2174,6 +2188,8 @@ static int open_output_file(OptionsContext *o, const char *filename)
                 int new_area;
                 ist = input_streams[i];
                 new_area = ist->st->codecpar->width * ist->st->codecpar->height + 100000000*!!ist->st->codec_info_nb_frames;
+                if (ist->user_set_discard == AVDISCARD_ALL)
+                    continue;
                 if((qcr!=MKTAG('A', 'P', 'I', 'C')) && (ist->st->disposition & AV_DISPOSITION_ATTACHED_PIC))
                     new_area = 1;
                 if (ist->st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO &&
@@ -2195,6 +2211,8 @@ static int open_output_file(OptionsContext *o, const char *filename)
                 int score;
                 ist = input_streams[i];
                 score = ist->st->codecpar->channels + 100000000*!!ist->st->codec_info_nb_frames;
+                if (ist->user_set_discard == AVDISCARD_ALL)
+                    continue;
                 if (ist->st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO &&
                     score > best_score) {
                     best_score = score;
@@ -2216,6 +2234,8 @@ static int open_output_file(OptionsContext *o, const char *filename)
                     AVCodec const *output_codec =
                         avcodec_find_encoder(oc->oformat->subtitle_codec);
                     int input_props = 0, output_props = 0;
+                    if (input_streams[i]->user_set_discard == AVDISCARD_ALL)
+                        continue;
                     if (output_codec)
                         output_descriptor = avcodec_descriptor_get(output_codec->id);
                     if (input_descriptor)
@@ -2237,6 +2257,8 @@ static int open_output_file(OptionsContext *o, const char *filename)
         if (!o->data_disable ) {
             enum AVCodecID codec_id = av_guess_codec(oc->oformat, NULL, filename, NULL, AVMEDIA_TYPE_DATA);
             for (i = 0; codec_id != AV_CODEC_ID_NONE && i < nb_input_streams; i++) {
+                if (input_streams[i]->user_set_discard == AVDISCARD_ALL)
+                    continue;
                 if (input_streams[i]->st->codecpar->codec_type == AVMEDIA_TYPE_DATA
                     && input_streams[i]->st->codecpar->codec_id == codec_id )
                     new_data_stream(o, oc, i);
@@ -2275,6 +2297,11 @@ loop_end:
                 int src_idx = input_files[map->file_index]->ist_index + map->stream_index;
 
                 ist = input_streams[input_files[map->file_index]->ist_index + map->stream_index];
+                if (ist->user_set_discard == AVDISCARD_ALL) {
+                    av_log(NULL, AV_LOG_FATAL, "Stream #%d:%d is disabled and cannot be mapped.\n",
+                           map->file_index, map->stream_index);
+                    exit_program(1);
+                }
                 if(o->subtitle_disable && ist->st->codecpar->codec_type == AVMEDIA_TYPE_SUBTITLE)
                     continue;
                 if(o->   audio_disable && ist->st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO)