lavf: add seek2any to allow forcing seeking to non keyframes via AVOptions

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/avformat.h

@@ -1203,6 +1203,13 @@ typedef struct AVFormatContext {
      */
     unsigned int correct_ts_overflow;
 
+    /**
+     * Force seeking to any (also non key) frames.
+     * - encoding: unused
+     * - decoding: Set by user via AVOPtions (NO direct access)
+     */
+    int seek2any;
+
     /*****************************************************************
      * All fields below this line are not part of the public API. They
      * may not be used outside of libavformat and can be changed and

libavformat/options_table.h

@@ -48,6 +48,7 @@ static const AVOption options[]={
 {"keepside", "dont merge side data", 0, AV_OPT_TYPE_CONST, {.i64 = AVFMT_FLAG_KEEP_SIDE_DATA }, 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"},
 {"nobuffer", "reduce the latency introduced by optional buffering", 0, AV_OPT_TYPE_CONST, {.i64 = AVFMT_FLAG_NOBUFFER }, 0, INT_MAX, D, "fflags"},
+{"seek2any", "forces seeking to enable seek to any mode", OFFSET(seek2any), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, 1, D},
 {"analyzeduration", "specify how many microseconds are analyzed to probe the input", OFFSET(max_analyze_duration), AV_OPT_TYPE_INT, {.i64 = 5*AV_TIME_BASE }, 0, INT_MAX, D},
 {"cryptokey", "decryption key", OFFSET(key), AV_OPT_TYPE_BINARY, {.dbl = 0}, 0, 0, D},
 {"indexmem", "max memory used for timestamp index (per stream)", OFFSET(max_index_size), AV_OPT_TYPE_INT, {.i64 = 1<<20 }, 0, INT_MAX, D},

libavformat/utils.c

@@ -2092,6 +2092,9 @@ int avformat_seek_file(AVFormatContext *s, int stream_index, int64_t min_ts, int
     if(min_ts > ts || max_ts < ts)
         return -1;
 
+    if(s->seek2any>0)
+        flags |= AVSEEK_FLAG_ANY;
+
     if (s->iformat->read_seek2) {
         int ret;
         ff_read_frame_flush(s);