diff --git a/doc/APIchanges b/doc/APIchanges
index 436fb71acb..aadf164254 100644
--- a/doc/APIchanges
+++ b/doc/APIchanges
@@ -15,6 +15,11 @@ libavutil:     2015-08-28
 
 API changes, most recent first:
 
+2017-03-21 - xxxxxxx - lavf 57.66.105, lavc 57.83.101 - avformat.h, avcodec.h
+  Deprecate AVFMT_FLAG_KEEP_SIDE_DATA. It will be ignored after the next major
+  bump, and libavformat will behave as if it were always set.
+  Deprecate av_packet_merge_side_data() and av_packet_split_side_data().
+
 2016-03-20 - xxxxxxx - lavu 55.50.100 / 55.21.0 - imgutils.h
   Add av_image_copy_uc_from(), a version of av_image_copy() for copying
   from GPU mapped memory.
diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index ea3cb4506b..fbdf89216d 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -4576,9 +4576,13 @@ int av_packet_shrink_side_data(AVPacket *pkt, enum AVPacketSideDataType type,
 uint8_t* av_packet_get_side_data(const AVPacket *pkt, enum AVPacketSideDataType type,
                                  int *size);
 
+#if FF_API_MERGE_SD_API
+attribute_deprecated
 int av_packet_merge_side_data(AVPacket *pkt);
 
+attribute_deprecated
 int av_packet_split_side_data(AVPacket *pkt);
+#endif
 
 const char *av_packet_side_data_name(enum AVPacketSideDataType type);
 
diff --git a/libavcodec/avpacket.c b/libavcodec/avpacket.c
index 3ea2511dea..8420d8b258 100644
--- a/libavcodec/avpacket.c
+++ b/libavcodec/avpacket.c
@@ -379,6 +379,8 @@ const char *av_packet_side_data_name(enum AVPacketSideDataType type)
     return NULL;
 }
 
+#if FF_API_MERGE_SD_API
+
 #define FF_MERGE_MARKER 0x8c4d9d108e25e9feULL
 
 int av_packet_merge_side_data(AVPacket *pkt){
@@ -460,6 +462,8 @@ int av_packet_split_side_data(AVPacket *pkt){
     return 0;
 }
 
+#endif
+
 uint8_t *av_packet_pack_dictionary(AVDictionary *dict, int *size)
 {
     AVDictionaryEntry *t = NULL;
diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index 84c28c8396..9b055d2b3e 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -2263,7 +2263,11 @@ int attribute_align_arg avcodec_decode_video2(AVCodecContext *avctx, AVFrame *pi
 
     if ((avctx->codec->capabilities & AV_CODEC_CAP_DELAY) || avpkt->size ||
         (avctx->active_thread_type & FF_THREAD_FRAME)) {
+#if FF_API_MERGE_SD
+FF_DISABLE_DEPRECATION_WARNINGS
         int did_split = av_packet_split_side_data(&tmp);
+FF_ENABLE_DEPRECATION_WARNINGS
+#endif
         ret = apply_param_change(avctx, &tmp);
         if (ret < 0)
             goto fail;
@@ -2295,11 +2299,13 @@ fail:
         emms_c(); //needed to avoid an emms_c() call before every return;
 
         avctx->internal->pkt = NULL;
+#if FF_API_MERGE_SD
         if (did_split) {
             av_packet_free_side_data(&tmp);
             if(ret == tmp.size)
                 ret = avpkt->size;
         }
+#endif
         if (picture->flags & AV_FRAME_FLAG_DISCARD) {
             *got_picture_ptr = 0;
         }
@@ -2369,7 +2375,11 @@ int attribute_align_arg avcodec_decode_audio4(AVCodecContext *avctx,
         uint8_t discard_reason = 0;
         // copy to ensure we do not change avpkt
         AVPacket tmp = *avpkt;
+#if FF_API_MERGE_SD
+FF_DISABLE_DEPRECATION_WARNINGS
         int did_split = av_packet_split_side_data(&tmp);
+FF_ENABLE_DEPRECATION_WARNINGS
+#endif
         ret = apply_param_change(avctx, &tmp);
         if (ret < 0)
             goto fail;
@@ -2481,11 +2491,13 @@ FF_ENABLE_DEPRECATION_WARNINGS
         }
 fail:
         avctx->internal->pkt = NULL;
+#if FF_API_MERGE_SD
         if (did_split) {
             av_packet_free_side_data(&tmp);
             if(ret == tmp.size)
                 ret = avpkt->size;
         }
+#endif
 
         if (ret >= 0 && *got_frame_ptr) {
             if (!avctx->refcounted_frames) {
@@ -2682,6 +2694,8 @@ int avcodec_decode_subtitle2(AVCodecContext *avctx, AVSubtitle *sub,
     if ((avctx->codec->capabilities & AV_CODEC_CAP_DELAY) || avpkt->size) {
         AVPacket pkt_recoded;
         AVPacket tmp = *avpkt;
+#if FF_API_MERGE_SD
+FF_DISABLE_DEPRECATION_WARNINGS
         int did_split = av_packet_split_side_data(&tmp);
         //apply_param_change(avctx, &tmp);
 
@@ -2694,6 +2708,8 @@ int avcodec_decode_subtitle2(AVCodecContext *avctx, AVSubtitle *sub,
             memset(tmp.data + tmp.size, 0,
                    FFMIN(avpkt->size - tmp.size, AV_INPUT_BUFFER_PADDING_SIZE));
         }
+FF_ENABLE_DEPRECATION_WARNINGS
+#endif
 
         pkt_recoded = tmp;
         ret = recode_subtitle(avctx, &pkt_recoded, &tmp);
@@ -2753,11 +2769,13 @@ int avcodec_decode_subtitle2(AVCodecContext *avctx, AVSubtitle *sub,
             avctx->internal->pkt = NULL;
         }
 
+#if FF_API_MERGE_SD
         if (did_split) {
             av_packet_free_side_data(&tmp);
             if(ret == tmp.size)
                 ret = avpkt->size;
         }
+#endif
 
         if (*got_sub_ptr)
             avctx->frame_number++;
@@ -2873,12 +2891,18 @@ int attribute_align_arg avcodec_send_packet(AVCodecContext *avctx, const AVPacke
     if (avctx->codec->send_packet) {
         if (avpkt) {
             AVPacket tmp = *avpkt;
+#if FF_API_MERGE_SD
+FF_DISABLE_DEPRECATION_WARNINGS
             int did_split = av_packet_split_side_data(&tmp);
+FF_ENABLE_DEPRECATION_WARNINGS
+#endif
             ret = apply_param_change(avctx, &tmp);
             if (ret >= 0)
                 ret = avctx->codec->send_packet(avctx, &tmp);
+#if FF_API_MERGE_SD
             if (did_split)
                 av_packet_free_side_data(&tmp);
+#endif
             return ret;
         } else {
             return avctx->codec->send_packet(avctx, NULL);
diff --git a/libavcodec/version.h b/libavcodec/version.h
index 3ed5a718d4..ec8651f086 100644
--- a/libavcodec/version.h
+++ b/libavcodec/version.h
@@ -29,7 +29,7 @@
 
 #define LIBAVCODEC_VERSION_MAJOR  57
 #define LIBAVCODEC_VERSION_MINOR  83
-#define LIBAVCODEC_VERSION_MICRO 100
+#define LIBAVCODEC_VERSION_MICRO 101
 
 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
                                                LIBAVCODEC_VERSION_MINOR, \
@@ -157,6 +157,9 @@
 #ifndef FF_API_VAAPI_CONTEXT
 #define FF_API_VAAPI_CONTEXT     (LIBAVCODEC_VERSION_MAJOR < 58)
 #endif
+#ifndef FF_API_MERGE_SD
+#define FF_API_MERGE_SD          (LIBAVCODEC_VERSION_MAJOR < 58)
+#endif
 #ifndef FF_API_AVCTX_TIMEBASE
 #define FF_API_AVCTX_TIMEBASE    (LIBAVCODEC_VERSION_MAJOR < 59)
 #endif
@@ -229,5 +232,9 @@
 #ifndef FF_API_STRUCT_VAAPI_CONTEXT
 #define FF_API_STRUCT_VAAPI_CONTEXT (LIBAVCODEC_VERSION_MAJOR < 59)
 #endif
+#ifndef FF_API_MERGE_SD_API
+#define FF_API_MERGE_SD_API      (LIBAVCODEC_VERSION_MAJOR < 59)
+#endif
+
 
 #endif /* AVCODEC_VERSION_H */
diff --git a/libavformat/avformat.h b/libavformat/avformat.h
index 4c1b18e002..4ab217dc17 100644
--- a/libavformat/avformat.h
+++ b/libavformat/avformat.h
@@ -1468,7 +1468,9 @@ typedef struct AVFormatContext {
 #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)
-#define AVFMT_FLAG_KEEP_SIDE_DATA 0x40000 ///< Don't merge side data but keep it separate.
+#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.
+#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.
 #define AVFMT_FLAG_AUTO_BSF   0x200000 ///< Wait for packet data before writing a header, and add bitstream filters as requested by the muxer
diff --git a/libavformat/mux.c b/libavformat/mux.c
index e500531789..11b09f1b6e 100644
--- a/libavformat/mux.c
+++ b/libavformat/mux.c
@@ -752,7 +752,11 @@ static int write_packet(AVFormatContext *s, AVPacket *pkt)
         }
     }
 
+#if FF_API_LAVF_MERGE_SD
+FF_DISABLE_DEPRECATION_WARNINGS
     did_split = av_packet_split_side_data(pkt);
+FF_ENABLE_DEPRECATION_WARNINGS
+#endif
 
     if (!s->internal->header_written) {
         ret = s->internal->write_header_ret ? s->internal->write_header_ret : write_header_internal(s);
@@ -777,8 +781,12 @@ static int write_packet(AVFormatContext *s, AVPacket *pkt)
     }
 
 fail:
+#if FF_API_LAVF_MERGE_SD
+FF_DISABLE_DEPRECATION_WARNINGS
     if (did_split)
         av_packet_merge_side_data(pkt);
+FF_ENABLE_DEPRECATION_WARNINGS
+#endif
 
     if (ret < 0) {
         pkt->pts = pts_backup;
@@ -875,8 +883,12 @@ static int do_packet_auto_bsf(AVFormatContext *s, AVPacket *pkt) {
         }
     }
 
+#if FF_API_LAVF_MERGE_SD
+FF_DISABLE_DEPRECATION_WARNINGS
     if (st->internal->nb_bsfcs)
         av_packet_split_side_data(pkt);
+FF_ENABLE_DEPRECATION_WARNINGS
+#endif
 
     for (i = 0; i < st->internal->nb_bsfcs; i++) {
         AVBSFContext *ctx = st->internal->bsfcs[i];
diff --git a/libavformat/options_table.h b/libavformat/options_table.h
index a537dda95e..0c1915d6d4 100644
--- a/libavformat/options_table.h
+++ b/libavformat/options_table.h
@@ -48,7 +48,9 @@ static const AVOption avformat_options[] = {
 {"igndts", "ignore dts", 0, AV_OPT_TYPE_CONST, {.i64 = AVFMT_FLAG_IGNDTS }, INT_MIN, INT_MAX, D, "fflags"},
 {"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"},
+#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"},
 {"nobuffer", "reduce the latency introduced by optional buffering", 0, AV_OPT_TYPE_CONST, {.i64 = AVFMT_FLAG_NOBUFFER }, 0, INT_MAX, D, "fflags"},
diff --git a/libavformat/utils.c b/libavformat/utils.c
index 37d7024465..8227d1bbe1 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -1675,8 +1675,12 @@ FF_ENABLE_DEPRECATION_WARNINGS
             st->inject_global_side_data = 0;
         }
 
+#if FF_API_LAVF_MERGE_SD
+FF_DISABLE_DEPRECATION_WARNINGS
         if (!(s->flags & AVFMT_FLAG_KEEP_SIDE_DATA))
             av_packet_merge_side_data(pkt);
+FF_ENABLE_DEPRECATION_WARNINGS
+#endif
     }
 
     av_opt_get_dict_val(s, "metadata", AV_OPT_SEARCH_CHILDREN, &metadata);
diff --git a/libavformat/version.h b/libavformat/version.h
index dc689d45fb..bfc42e3f15 100644
--- a/libavformat/version.h
+++ b/libavformat/version.h
@@ -33,7 +33,7 @@
 // Also please add any ticket numbers that you believe might be affected here
 #define LIBAVFORMAT_VERSION_MAJOR  57
 #define LIBAVFORMAT_VERSION_MINOR  66
-#define LIBAVFORMAT_VERSION_MICRO 104
+#define LIBAVFORMAT_VERSION_MICRO 105
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
                                                LIBAVFORMAT_VERSION_MINOR, \
@@ -88,6 +88,12 @@
 #ifndef FF_API_HLS_WRAP
 #define FF_API_HLS_WRAP                 (LIBAVFORMAT_VERSION_MAJOR < 58)
 #endif
+#ifndef FF_API_LAVF_MERGE_SD
+#define FF_API_LAVF_MERGE_SD            (LIBAVFORMAT_VERSION_MAJOR < 58)
+#endif
+#ifndef FF_API_LAVF_KEEPSIDE_FLAG
+#define FF_API_LAVF_KEEPSIDE_FLAG       (LIBAVFORMAT_VERSION_MAJOR < 58)
+#endif
 
 
 #ifndef FF_API_R_FRAME_RATE