lavf: add a flag to enable/disable automatic bitstream filtering

This is mostly useful for muxers that wrap other muxers, such as dashenc
and segment. The actual duplicated bitstream filtering is largely harmless,
but delaying the header can cause problems when the muxer intended the header
to be written to a separate file.

diff --git a/libavformat/avformat.h b/libavformat/avformat.h
index 74915a1482295b0fc054ac3a37f01e1d01736d6f..43b225bb5acc5e7be3dab77ec066cd3ae7d64aaf 100644 (file)
--- a/libavformat/avformat.h
+++ b/libavformat/avformat.h
@@ -1449,6 +1449,7 @@ typedef struct AVFormatContext {
 #define AVFMT_FLAG_KEEP_SIDE_DATA 0x40000 ///< Don't merge side data but keep it separate.
 #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.
+#define AVFMT_FLAG_AUTO_BSF   0x200000 ///< Wait for packet data before writing a header, and add bitstream filters as requested by the muxer
 
     /**
      * Maximum size of the data read from input for determining

diff --git a/libavformat/mux.c b/libavformat/mux.c
index 176af59f1388e2277142784c874ad8e82109e8a0..bbfc0fccb867a031f93a039dc5b28d5363771e0a 100644 (file)
--- a/libavformat/mux.c
+++ b/libavformat/mux.c
@@ -500,7 +500,7 @@ int avformat_write_header(AVFormatContext *s, AVDictionary **options)
     if ((ret = init_muxer(s, options)) < 0)
         return ret;
 
-    if (!s->oformat->check_bitstream) {
+    if (!(s->oformat->check_bitstream && s->flags & AVFMT_FLAG_AUTO_BSF)) {
         ret = write_header_internal(s);
         if (ret < 0)
             goto fail;
@@ -830,6 +830,9 @@ static int do_packet_auto_bsf(AVFormatContext *s, AVPacket *pkt) {
     AVStream *st = s->streams[pkt->stream_index];
     int i, ret;
 
+    if (!(s->flags & AVFMT_FLAG_AUTO_BSF))
+        return 1;
+
     if (s->oformat->check_bitstream) {
         if (!st->internal->bitstream_checked) {
             if ((ret = s->oformat->check_bitstream(s, pkt)) < 0)

diff --git a/libavformat/options_table.h b/libavformat/options_table.h
index 699809a84c32d880239a720534b33d579553bbda..9d61d5a158b2688efd8884629d757b97ba6b5be9 100644 (file)
--- a/libavformat/options_table.h
+++ b/libavformat/options_table.h
@@ -39,7 +39,7 @@ static const AVOption avformat_options[] = {
 {"probesize", "set probing size", OFFSET(probesize), AV_OPT_TYPE_INT64, {.i64 = 5000000 }, 32, INT64_MAX, D},
 {"formatprobesize", "number of bytes to probe file format", OFFSET(format_probesize), AV_OPT_TYPE_INT, {.i64 = PROBE_BUF_MAX}, 0, INT_MAX-1, D},
 {"packetsize", "set packet size", OFFSET(packet_size), AV_OPT_TYPE_INT, {.i64 = DEFAULT }, 0, INT_MAX, E},
-{"fflags", NULL, OFFSET(flags), AV_OPT_TYPE_FLAGS, {.i64 = AVFMT_FLAG_FLUSH_PACKETS }, INT_MIN, INT_MAX, D|E, "fflags"},
+{"fflags", NULL, OFFSET(flags), AV_OPT_TYPE_FLAGS, {.i64 = AVFMT_FLAG_FLUSH_PACKETS | AVFMT_FLAG_AUTO_BSF }, INT_MIN, INT_MAX, D|E, "fflags"},
 {"flush_packets", "reduce the latency by flushing out packets immediately", 0, AV_OPT_TYPE_CONST, {.i64 = AVFMT_FLAG_FLUSH_PACKETS }, INT_MIN, INT_MAX, E, "fflags"},
 {"ignidx", "ignore index", 0, AV_OPT_TYPE_CONST, {.i64 = AVFMT_FLAG_IGNIDX }, INT_MIN, INT_MAX, D, "fflags"},
 {"genpts", "generate pts", 0, AV_OPT_TYPE_CONST, {.i64 = AVFMT_FLAG_GENPTS }, INT_MIN, INT_MAX, D, "fflags"},
@@ -55,6 +55,7 @@ static const AVOption avformat_options[] = {
 {"seek2any", "allow seeking to non-keyframes on demuxer level when supported", OFFSET(seek2any), AV_OPT_TYPE_BOOL, {.i64 = 0 }, 0, 1, D},
 {"bitexact", "do not write random/volatile data", 0, AV_OPT_TYPE_CONST, { .i64 = AVFMT_FLAG_BITEXACT }, 0, 0, E, "fflags" },
 {"shortest", "stop muxing with the shortest stream", 0, AV_OPT_TYPE_CONST, { .i64 = AVFMT_FLAG_SHORTEST }, 0, 0, E, "fflags" },
+{"autobsf", "add needed bsfs automatically (delays header until each stream's first packet is written)", 0, AV_OPT_TYPE_CONST, { .i64 = AVFMT_FLAG_AUTO_BSF }, 0, 0, E, "fflags" },
 {"analyzeduration", "specify how many microseconds are analyzed to probe the input", OFFSET(max_analyze_duration), AV_OPT_TYPE_INT64, {.i64 = 0 }, 0, INT64_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},