diff --git a/doc/APIchanges b/doc/APIchanges
index a1c501d9d8..4137775fc1 100644
--- a/doc/APIchanges
+++ b/doc/APIchanges
@@ -15,6 +15,10 @@ libavutil:     2012-10-22
 
 API changes, most recent first:
 
+2014-05-xx - xxxxxxx - lavf 55.17.0 - avformat.h
+  Add AVMFT_FLAG_BITEXACT flag. Muxers now use it instead of checking
+  CODEC_FLAG_BITEXACT on the first stream.
+
 2014-05-15 - xxxxxxx - lswr 0.19.100 - swresample.h
   Add swr_close()
 
diff --git a/libavformat/avformat.h b/libavformat/avformat.h
index d09745acb8..55a3cfbd35 100644
--- a/libavformat/avformat.h
+++ b/libavformat/avformat.h
@@ -1252,6 +1252,13 @@ typedef struct AVFormatContext {
 #define AVFMT_FLAG_CUSTOM_IO    0x0080 ///< The caller has supplied a custom AVIOContext, don't avio_close() it.
 #define AVFMT_FLAG_DISCARD_CORRUPT  0x0100 ///< Discard frames marked corrupted
 #define AVFMT_FLAG_FLUSH_PACKETS    0x0200 ///< Flush the AVIOContext every packet.
+/**
+ * When muxing, try to avoid writing any random/volatile data to the output.
+ * This includes any random IDs, real-time timestamps/dates, muxer version, etc.
+ *
+ * This flag is mainly intended for testing.
+ */
+#define AVFMT_FLAG_BITEXACT         0x0400
 #define AVFMT_FLAG_MP4A_LATM    0x8000 ///< Enable RTP MP4A-LATM payload
 #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)
diff --git a/libavformat/flacenc.c b/libavformat/flacenc.c
index 0eca5aaccb..d92801807e 100644
--- a/libavformat/flacenc.c
+++ b/libavformat/flacenc.c
@@ -98,7 +98,7 @@ static int flac_write_header(struct AVFormatContext *s)
         return ret;
 
     ret = flac_write_block_comment(s->pb, &s->metadata, !padding,
-                                   codec->flags & CODEC_FLAG_BITEXACT);
+                                   s->flags & AVFMT_FLAG_BITEXACT);
     if (ret)
         return ret;
 
diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
index 8b19ae3565..17eb318aad 100644
--- a/libavformat/matroskaenc.c
+++ b/libavformat/matroskaenc.c
@@ -1160,7 +1160,7 @@ static int mkv_write_header(AVFormatContext *s)
     put_ebml_uint(pb, MATROSKA_ID_TIMECODESCALE, 1000000);
     if ((tag = av_dict_get(s->metadata, "title", NULL, 0)))
         put_ebml_string(pb, MATROSKA_ID_TITLE, tag->value);
-    if (!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
+    if (!(s->flags & AVFMT_FLAG_BITEXACT)) {
         uint32_t segment_uid[4];
         AVLFG lfg;
 
diff --git a/libavformat/movenc.c b/libavformat/movenc.c
index b3a7649454..adcbcf2c0f 100644
--- a/libavformat/movenc.c
+++ b/libavformat/movenc.c
@@ -3872,7 +3872,7 @@ static int mov_write_header(AVFormatContext *s)
     }
 
     for (i = 0; i < s->nb_streams; i++)
-        if (s->streams[i]->codec->flags & CODEC_FLAG_BITEXACT)
+        if (s->flags & AVFMT_FLAG_BITEXACT)
             mov->exact = 1;
 
     /* Set the FRAGMENT flag if any of the fragmentation methods are
diff --git a/libavformat/mux.c b/libavformat/mux.c
index cbe17f5d78..175f157741 100644
--- a/libavformat/mux.c
+++ b/libavformat/mux.c
@@ -235,6 +235,11 @@ static int init_muxer(AVFormatContext *s, AVDictionary **options)
         (ret = av_opt_set_dict2(s->priv_data, &tmp, AV_OPT_SEARCH_CHILDREN)) < 0)
         goto fail;
 
+#if FF_API_LAVF_BITEXACT
+    if (s->nb_streams && s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)
+        s->flags |= AVFMT_FLAG_BITEXACT;
+#endif
+
     // some sanity checks
     if (s->nb_streams == 0 && !(of->flags & AVFMT_NOSTREAMS)) {
         av_log(s, AV_LOG_ERROR, "No streams to mux were specified\n");
@@ -340,7 +345,7 @@ static int init_muxer(AVFormatContext *s, AVDictionary **options)
     }
 
     /* set muxer identification string */
-    if (s->nb_streams && !(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT)) {
+    if (!(s->flags & AVFMT_FLAG_BITEXACT)) {
         av_dict_set(&s->metadata, "encoder", LIBAVFORMAT_IDENT, 0);
     } else {
         av_dict_set(&s->metadata, "encoder", NULL, 0);
diff --git a/libavformat/mxfenc.c b/libavformat/mxfenc.c
index 5e77a3f068..6f3226b968 100644
--- a/libavformat/mxfenc.c
+++ b/libavformat/mxfenc.c
@@ -618,7 +618,7 @@ static void mxf_write_identification(AVFormatContext *s)
     mxf_write_metadata_key(pb, 0x013000);
     PRINT_KEY(s, "identification key", pb->buf_ptr - 16);
 
-    version = s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT ?
+    version = s->flags & AVFMT_FLAG_BITEXACT ?
         "0.0.0" : AV_STRINGIFY(LIBAVFORMAT_VERSION);
     length = 84 + (strlen(company)+strlen(product)+strlen(version))*2; // utf-16
     klv_encode_ber_length(pb, length);
@@ -1777,7 +1777,7 @@ static int mxf_write_header(AVFormatContext *s)
         mxf->essence_container_count = 1;
     }
 
-    if (!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT))
+    if (!(s->flags & AVFMT_FLAG_BITEXACT))
         mxf_gen_umid(s);
 
     for (i = 0; i < s->nb_streams; i++) {
diff --git a/libavformat/oggenc.c b/libavformat/oggenc.c
index 4ba6940d10..375abadd44 100644
--- a/libavformat/oggenc.c
+++ b/libavformat/oggenc.c
@@ -432,7 +432,7 @@ static int ogg_write_header(AVFormatContext *s)
 
         oggstream->page.stream_index = i;
 
-        if (!(st->codec->flags & CODEC_FLAG_BITEXACT))
+        if (!(s->flags & AVFMT_FLAG_BITEXACT))
             do {
                 serial_num = av_get_random_seed();
                 for (j = 0; j < i; j++) {
@@ -448,7 +448,7 @@ static int ogg_write_header(AVFormatContext *s)
         st->priv_data = oggstream;
         if (st->codec->codec_id == AV_CODEC_ID_FLAC) {
             int err = ogg_build_flac_headers(st->codec, oggstream,
-                                             st->codec->flags & CODEC_FLAG_BITEXACT,
+                                             s->flags & AVFMT_FLAG_BITEXACT,
                                              &st->metadata);
             if (err) {
                 av_log(s, AV_LOG_ERROR, "Error writing FLAC headers\n");
@@ -457,7 +457,7 @@ static int ogg_write_header(AVFormatContext *s)
             }
         } else if (st->codec->codec_id == AV_CODEC_ID_SPEEX) {
             int err = ogg_build_speex_headers(st->codec, oggstream,
-                                              st->codec->flags & CODEC_FLAG_BITEXACT,
+                                              s->flags & AVFMT_FLAG_BITEXACT,
                                               &st->metadata);
             if (err) {
                 av_log(s, AV_LOG_ERROR, "Error writing Speex headers\n");
@@ -466,7 +466,7 @@ static int ogg_write_header(AVFormatContext *s)
             }
         } else if (st->codec->codec_id == AV_CODEC_ID_OPUS) {
             int err = ogg_build_opus_headers(st->codec, oggstream,
-                                             st->codec->flags & CODEC_FLAG_BITEXACT,
+                                             s->flags & AVFMT_FLAG_BITEXACT,
                                              &st->metadata);
             if (err) {
                 av_log(s, AV_LOG_ERROR, "Error writing Opus headers\n");
@@ -487,7 +487,7 @@ static int ogg_write_header(AVFormatContext *s)
                 return -1;
             }
 
-            p = ogg_write_vorbiscomment(7, st->codec->flags & CODEC_FLAG_BITEXACT,
+            p = ogg_write_vorbiscomment(7, s->flags & AVFMT_FLAG_BITEXACT,
                                         &oggstream->header_len[1], &st->metadata,
                                         framing_bit);
             oggstream->header[1] = p;
diff --git a/libavformat/options_table.h b/libavformat/options_table.h
index be5003403c..359b38483a 100644
--- a/libavformat/options_table.h
+++ b/libavformat/options_table.h
@@ -50,6 +50,7 @@ static const AVOption avformat_options[] = {
 {"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", "allow seeking to non-keyframes on demuxer level when supported", OFFSET(seek2any), AV_OPT_TYPE_INT, {.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" },
 {"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},
diff --git a/libavformat/version.h b/libavformat/version.h
index 8905fb5b25..c6667ca7bf 100644
--- a/libavformat/version.h
+++ b/libavformat/version.h
@@ -30,8 +30,8 @@
 #include "libavutil/version.h"
 
 #define LIBAVFORMAT_VERSION_MAJOR 55
-#define LIBAVFORMAT_VERSION_MINOR 37
-#define LIBAVFORMAT_VERSION_MICRO 102
+#define LIBAVFORMAT_VERSION_MINOR 38
+#define LIBAVFORMAT_VERSION_MICRO 100
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
                                                LIBAVFORMAT_VERSION_MINOR, \
@@ -51,6 +51,9 @@
 #ifndef FF_API_REFERENCE_DTS
 #define FF_API_REFERENCE_DTS            (LIBAVFORMAT_VERSION_MAJOR < 56)
 #endif
+#ifndef FF_API_LAVF_BITEXACT
+#define FF_API_LAVF_BITEXACT            (LIBAVFORMAT_VERSION_MAJOR < 56)
+#endif
 
 #ifndef FF_API_ALLOC_OUTPUT_CONTEXT
 #define FF_API_ALLOC_OUTPUT_CONTEXT    (LIBAVFORMAT_VERSION_MAJOR < 56)
diff --git a/tests/fate-run.sh b/tests/fate-run.sh
index 74f4525b9e..60cb569faf 100755
--- a/tests/fate-run.sh
+++ b/tests/fate-run.sh
@@ -127,7 +127,7 @@ enc_dec_pcm(){
     ffmpeg -flags +bitexact -i ${encfile} -c:a pcm_${pcm_fmt} -f ${dec_fmt} -
 }
 
-FLAGS="-flags +bitexact -sws_flags +accurate_rnd+bitexact"
+FLAGS="-flags +bitexact -sws_flags +accurate_rnd+bitexact -fflags +bitexact"
 DEC_OPTS="-threads $threads -idct simple $FLAGS"
 ENC_OPTS="-threads 1        -idct simple -dct fastint"
 
diff --git a/tests/fate/filter-audio.mak b/tests/fate/filter-audio.mak
index 725fb7ea27..210b89eb07 100644
--- a/tests/fate/filter-audio.mak
+++ b/tests/fate/filter-audio.mak
@@ -56,7 +56,7 @@ FATE_FILTER_CHANNELMAP += fate-filter-channelmap-one-int
 fate-filter-channelmap-one-int: tests/data/filtergraphs/channelmap_one_int
 fate-filter-channelmap-one-int: SRC = $(TARGET_PATH)/tests/data/asynth-44100-6.wav
 fate-filter-channelmap-one-int: tests/data/asynth-44100-6.wav
-fate-filter-channelmap-one-int: CMD = md5 -i $(SRC) -filter_complex_script $(TARGET_PATH)/tests/data/filtergraphs/channelmap_one_int -f wav -flags +bitexact
+fate-filter-channelmap-one-int: CMD = md5 -i $(SRC) -filter_complex_script $(TARGET_PATH)/tests/data/filtergraphs/channelmap_one_int -f wav -fflags +bitexact
 fate-filter-channelmap-one-int: CMP = oneline
 fate-filter-channelmap-one-int: REF = 428b8f9fac6d57147069b97335019ef5
 
@@ -64,7 +64,7 @@ FATE_FILTER_CHANNELMAP += fate-filter-channelmap-one-str
 fate-filter-channelmap-one-str: tests/data/filtergraphs/channelmap_one_str
 fate-filter-channelmap-one-str: SRC = $(TARGET_PATH)/tests/data/asynth-44100-2.wav
 fate-filter-channelmap-one-str: tests/data/asynth-44100-2.wav
-fate-filter-channelmap-one-str: CMD = md5 -i $(SRC) -filter_complex_script $(TARGET_PATH)/tests/data/filtergraphs/channelmap_one_str -f wav -flags +bitexact
+fate-filter-channelmap-one-str: CMD = md5 -i $(SRC) -filter_complex_script $(TARGET_PATH)/tests/data/filtergraphs/channelmap_one_str -f wav -fflags +bitexact
 fate-filter-channelmap-one-str: CMP = oneline
 fate-filter-channelmap-one-str: REF = e788890db6a11c2fb29d7c4229072d49
 
diff --git a/tests/fate/video.mak b/tests/fate/video.mak
index fd42068eea..44c7c72260 100644
--- a/tests/fate/video.mak
+++ b/tests/fate/video.mak
@@ -181,7 +181,7 @@ FATE_VIDEO-$(call DEMDEC, MSNWC_TCP, MIMIC) += fate-mimic
 fate-mimic: CMD = framecrc -idct simple -i $(TARGET_SAMPLES)/mimic/mimic2-womanloveffmpeg.cam
 
 FATE_VIDEO-$(call DEMDEC, MOV, MJPEGB) += fate-mjpegb
-fate-mjpegb: CMD = framecrc -idct simple -flags +bitexact -i $(TARGET_SAMPLES)/mjpegb/mjpegb_part.mov -an
+fate-mjpegb: CMD = framecrc -idct simple -fflags +bitexact -i $(TARGET_SAMPLES)/mjpegb/mjpegb_part.mov -an
 
 FATE_VIDEO-$(call DEMDEC, MVI, MOTIONPIXELS) += fate-motionpixels
 fate-motionpixels: CMD = framecrc -i $(TARGET_SAMPLES)/motion-pixels/INTRO-partial.MVI -an -pix_fmt rgb24 -vframes 111
@@ -270,7 +270,7 @@ fate-v410dec: CMD = framecrc -i $(TARGET_SAMPLES)/v410/lenav410.mov -pix_fmt yuv
 
 FATE_VIDEO-$(call ENCDEC, V410 PGMYUV, AVI IMAGE2) += fate-v410enc
 fate-v410enc: $(VREF)
-fate-v410enc: CMD = md5 -f image2 -vcodec pgmyuv -i $(TARGET_PATH)/tests/vsynth1/%02d.pgm -flags +bitexact -vcodec v410 -f avi
+fate-v410enc: CMD = md5 -f image2 -vcodec pgmyuv -i $(TARGET_PATH)/tests/vsynth1/%02d.pgm -fflags +bitexact -vcodec v410 -f avi
 
 FATE_VIDEO-$(call DEMDEC, SIFF, VB) += fate-vb
 fate-vb: CMD = framecrc -i $(TARGET_SAMPLES)/SIFF/INTRO_B.VB -t 3 -pix_fmt rgb24 -an
diff --git a/tests/fate/wavpack.mak b/tests/fate/wavpack.mak
index 98e09980f7..240f5ead94 100644
--- a/tests/fate/wavpack.mak
+++ b/tests/fate/wavpack.mak
@@ -89,12 +89,12 @@ FATE_WAVPACK-$(call DEMDEC, MATROSKA, WAVPACK) += fate-wavpack-matroskamode
 fate-wavpack-matroskamode: CMD = md5 -i $(TARGET_SAMPLES)/wavpack/special/matroska_mode.mka -f s16le
 
 FATE_WAVPACK-$(call DEMMUX, WV, MATROSKA) += fate-wavpack-matroska_mux-mono
-fate-wavpack-matroska_mux-mono: CMD = md5 -i $(TARGET_SAMPLES)/wavpack/num_channels/mono_16bit_int.wv -c copy -flags +bitexact -f matroska
+fate-wavpack-matroska_mux-mono: CMD = md5 -i $(TARGET_SAMPLES)/wavpack/num_channels/mono_16bit_int.wv -c copy -fflags +bitexact -f matroska
 fate-wavpack-matroska_mux-mono: CMP = oneline
 fate-wavpack-matroska_mux-mono: REF = a2987e2e51e01a35e47e7da13eb47a35
 
 FATE_WAVPACK-$(call DEMMUX, WV, MATROSKA) += fate-wavpack-matroska_mux-61
-fate-wavpack-matroska_mux-61: CMD = md5 -i $(TARGET_SAMPLES)/wavpack/num_channels/eva_2.22_6.1_16bit-partial.wv -c copy -flags +bitexact -f matroska
+fate-wavpack-matroska_mux-61: CMD = md5 -i $(TARGET_SAMPLES)/wavpack/num_channels/eva_2.22_6.1_16bit-partial.wv -c copy -fflags +bitexact -f matroska
 fate-wavpack-matroska_mux-61: CMP = oneline
 fate-wavpack-matroska_mux-61: REF = ffba4ddea1ba71f7a5901d9ed1a267be
 
diff --git a/tests/regression-funcs.sh b/tests/regression-funcs.sh
index da17ac587f..86bc446a34 100755
--- a/tests/regression-funcs.sh
+++ b/tests/regression-funcs.sh
@@ -44,7 +44,7 @@ echov(){
 . $(dirname $0)/md5.sh
 
 AVCONV_OPTS="-nostats -y -cpuflags $cpuflags"
-COMMON_OPTS="-flags +bitexact -idct simple -sws_flags +accurate_rnd+bitexact"
+COMMON_OPTS="-flags +bitexact -idct simple -sws_flags +accurate_rnd+bitexact -fflags +bitexact"
 DEC_OPTS="$COMMON_OPTS -threads $threads"
 ENC_OPTS="$COMMON_OPTS -threads 1 -dct fastint"