avformat: remove use of deprecated AVFMT_FLAG_KEEP_SIDE_DATA flag

It has no effect whatsoever since the major bump.
Replace the flag's documentation to reflect this as well.

Signed-off-by: James Almer <jamrial@gmail.com>

fftools/ffmpeg_opt.c

@@ -991,7 +991,6 @@ static int open_input_file(OptionsContext *o, const char *filename)
         print_error(filename, AVERROR(ENOMEM));
         exit_program(1);
     }
-    ic->flags |= AVFMT_FLAG_KEEP_SIDE_DATA;
     if (o->nb_audio_sample_rate) {
         av_dict_set_int(&o->g->format_opts, "sample_rate", o->audio_sample_rate[o->nb_audio_sample_rate - 1].u.i, 0);
     }
@@ -1989,7 +1988,6 @@ static int read_ffserver_streams(OptionsContext *o, AVFormatContext *s, const ch
     int i, err;
     AVFormatContext *ic = avformat_alloc_context();
 
-    ic->flags |= AVFMT_FLAG_KEEP_SIDE_DATA;
     ic->interrupt_callback = int_cb;
     err = avformat_open_input(&ic, filename, NULL, NULL);
     if (err < 0)

fftools/ffprobe.c

@@ -2828,8 +2828,6 @@ static int open_input_file(InputFile *ifile, const char *filename)
         exit_program(1);
     }
 
-    fmt_ctx->flags |= AVFMT_FLAG_KEEP_SIDE_DATA;
-
     if (!av_dict_get(format_opts, "scan_all_pmts", NULL, AV_DICT_MATCH_CASE)) {
         av_dict_set(&format_opts, "scan_all_pmts", "1", AV_DICT_DONT_OVERWRITE);
         scan_all_pmts_set = 1;

libavformat/avformat.h

@@ -1444,7 +1444,7 @@ typedef struct AVFormatContext {
 #define AVFMT_FLAG_SORT_DTS    0x10000 ///< try to interleave outputted packets by dts (using this flag can slow demuxing down)
 #define AVFMT_FLAG_PRIV_OPT    0x20000 ///< Enable use of private options by delaying codec open (this could be made default once all code is converted)
 #if FF_API_LAVF_KEEPSIDE_FLAG
-#define AVFMT_FLAG_KEEP_SIDE_DATA 0x40000 ///< Don't merge side data but keep it separate. Deprecated, will be the default.
+#define AVFMT_FLAG_KEEP_SIDE_DATA 0x40000 ///< Deprecated, does nothing.
 #endif
 #define AVFMT_FLAG_FAST_SEEK   0x80000 ///< Enable fast, but inaccurate seeks for some formats
 #define AVFMT_FLAG_SHORTEST   0x100000 ///< Stop muxing when the shortest stream stops.

libavformat/options_table.h

@@ -49,7 +49,7 @@ static const AVOption avformat_options[] = {
 {"discardcorrupt", "discard corrupted frames", 0, AV_OPT_TYPE_CONST, {.i64 = AVFMT_FLAG_DISCARD_CORRUPT }, INT_MIN, INT_MAX, D, "fflags"},
 {"sortdts", "try to interleave outputted packets by dts", 0, AV_OPT_TYPE_CONST, {.i64 = AVFMT_FLAG_SORT_DTS }, INT_MIN, INT_MAX, D, "fflags"},
 #if FF_API_LAVF_KEEPSIDE_FLAG
-{"keepside", "don't merge side data", 0, AV_OPT_TYPE_CONST, {.i64 = AVFMT_FLAG_KEEP_SIDE_DATA }, INT_MIN, INT_MAX, D, "fflags"},
+{"keepside", "deprecated, does nothing", 0, AV_OPT_TYPE_CONST, {.i64 = AVFMT_FLAG_KEEP_SIDE_DATA }, INT_MIN, INT_MAX, D, "fflags"},
 #endif
 {"fastseek", "fast but inaccurate seeks", 0, AV_OPT_TYPE_CONST, {.i64 = AVFMT_FLAG_FAST_SEEK }, INT_MIN, INT_MAX, D, "fflags"},
 {"latm", "enable RTP MP4A-LATM payload", 0, AV_OPT_TYPE_CONST, {.i64 = AVFMT_FLAG_MP4A_LATM }, INT_MIN, INT_MAX, E, "fflags"},

libavformat/tests/seek.c

@@ -67,8 +67,6 @@ int main(int argc, char **argv)
     int frame_count = 1;
     int duration = 4;
 
-    ic->flags |= AVFMT_FLAG_KEEP_SIDE_DATA;
-
     for(i=2; i<argc; i+=2){
         if       (!strcmp(argv[i], "-seekforw")){
             seekfirst = atoi(argv[i+1]);