From fee249b30aa0bb6bed96be9601520346c65b8510 Mon Sep 17 00:00:00 2001
From: Anton Khirnov <anton@khirnov.net>
Date: Wed, 3 Aug 2022 12:02:59 +0200
Subject: fftools/ffmpeg: deprecate specifying a sync stream with -map

It has not had any effect whatsoever for over 10 years.
---
 doc/ffmpeg.texi      |  6 ++----
 fftools/ffmpeg.h     |  3 +--
 fftools/ffmpeg_opt.c | 41 +++++++----------------------------------
 3 files changed, 10 insertions(+), 40 deletions(-)

diff --git a/doc/ffmpeg.texi b/doc/ffmpeg.texi
index 2fb0bc8ffa..20747ebb8e 100644
--- a/doc/ffmpeg.texi
+++ b/doc/ffmpeg.texi
@@ -1411,14 +1411,12 @@ Set the size of the canvas used to render subtitles.
 @section Advanced options
 
 @table @option
-@item -map [-]@var{input_file_id}[:@var{stream_specifier}][?][,@var{sync_file_id}[:@var{stream_specifier}]] | @var{[linklabel]} (@emph{output})
+@item -map [-]@var{input_file_id}[:@var{stream_specifier}][?] | @var{[linklabel]} (@emph{output})
 
 Designate one or more input streams as a source for the output file. Each input
 stream is identified by the input file index @var{input_file_id} and
 the input stream index @var{input_stream_id} within the input
-file. Both indices start at 0. If specified,
-@var{sync_file_id}:@var{stream_specifier} sets which input stream
-is used as a presentation sync reference.
+file. Both indices start at 0.
 
 The first @code{-map} option on the command line specifies the
 source for output stream 0, the second @code{-map} option specifies
diff --git a/fftools/ffmpeg.h b/fftools/ffmpeg.h
index b7d62957f8..6b09846825 100644
--- a/fftools/ffmpeg.h
+++ b/fftools/ffmpeg.h
@@ -52,6 +52,7 @@
 // deprecated features
 #define FFMPEG_OPT_PSNR 1
 #define FFMPEG_OPT_MAP_CHANNEL 1
+#define FFMPEG_OPT_MAP_SYNC 1
 
 enum VideoSyncMethod {
     VSYNC_AUTO = -1,
@@ -81,8 +82,6 @@ typedef struct StreamMap {
     int disabled;           /* 1 is this mapping is disabled by a negative map */
     int file_index;
     int stream_index;
-    int sync_file_index;
-    int sync_stream_index;
     char *linklabel;       /* name of an output link, for mapping lavfi outputs */
 } StreamMap;
 
diff --git a/fftools/ffmpeg_opt.c b/fftools/ffmpeg_opt.c
index 0cd807c9c8..bd3a34960c 100644
--- a/fftools/ffmpeg_opt.c
+++ b/fftools/ffmpeg_opt.c
@@ -415,9 +415,10 @@ static int opt_map(void *optctx, const char *opt, const char *arg)
     OptionsContext *o = optctx;
     StreamMap *m = NULL;
     int i, negative = 0, file_idx, disabled = 0;
-    int sync_file_idx = -1, sync_stream_idx = 0;
-    char *p, *sync;
-    char *map;
+#if FFMPEG_OPT_MAP_SYNC
+    char *sync;
+#endif
+    char *map, *p;
     char *allow_unused;
 
     if (*arg == '-') {
@@ -428,33 +429,13 @@ static int opt_map(void *optctx, const char *opt, const char *arg)
     if (!map)
         return AVERROR(ENOMEM);
 
+#if FFMPEG_OPT_MAP_SYNC
     /* parse sync stream first, just pick first matching stream */
     if (sync = strchr(map, ',')) {
         *sync = 0;
-        sync_file_idx = strtol(sync + 1, &sync, 0);
-        if (sync_file_idx >= nb_input_files || sync_file_idx < 0) {
-            av_log(NULL, AV_LOG_FATAL, "Invalid sync file index: %d.\n", sync_file_idx);
-            exit_program(1);
-        }
-        if (*sync)
-            sync++;
-        for (i = 0; i < input_files[sync_file_idx]->nb_streams; i++)
-            if (check_stream_specifier(input_files[sync_file_idx]->ctx,
-                                       input_files[sync_file_idx]->ctx->streams[i], sync) == 1) {
-                sync_stream_idx = i;
-                break;
-            }
-        if (i == input_files[sync_file_idx]->nb_streams) {
-            av_log(NULL, AV_LOG_FATAL, "Sync stream specification in map %s does not "
-                                       "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);
-        }
+        av_log(NULL, AV_LOG_WARNING, "Specifying a sync stream is deprecated and has no effect\n");
     }
+#endif
 
 
     if (map[0] == '[') {
@@ -499,14 +480,6 @@ static int opt_map(void *optctx, const char *opt, const char *arg)
 
                 m->file_index   = file_idx;
                 m->stream_index = i;
-
-                if (sync_file_idx >= 0) {
-                    m->sync_file_index   = sync_file_idx;
-                    m->sync_stream_index = sync_stream_idx;
-                } else {
-                    m->sync_file_index   = file_idx;
-                    m->sync_stream_index = i;
-                }
             }
     }
 
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