diff --git a/ffserver.c b/ffserver.c
index 078ee116e1..bc056dd9f0 100644
--- a/ffserver.c
+++ b/ffserver.c
@@ -2260,7 +2260,7 @@ static int http_prepare_data(HTTPContext *c)
             /* XXX: potential leak */
             return -1;
         }
-        c->fmt_ctx.pb->is_streamed = 1;
+        c->fmt_ctx.pb->seekable = 0;
 
         /*
          * HACK to avoid mpeg ps muxer to spit many underflow errors
@@ -2399,7 +2399,7 @@ static int http_prepare_data(HTTPContext *c)
                     }
                     ost = ctx->streams[pkt.stream_index];
 
-                    ctx->pb->is_streamed = 1;
+                    ctx->pb->seekable = 0;
                     if (pkt.dts != AV_NOPTS_VALUE)
                         pkt.dts = av_rescale_q(pkt.dts, ist->time_base, ost->time_base);
                     if (pkt.pts != AV_NOPTS_VALUE)
@@ -2436,7 +2436,7 @@ static int http_prepare_data(HTTPContext *c)
             /* XXX: potential leak */
             return -1;
         }
-        c->fmt_ctx.pb->is_streamed = 1;
+        c->fmt_ctx.pb->seekable = 0;
         av_write_trailer(ctx);
         len = url_close_dyn_buf(ctx->pb, &c->pb_buffer);
         c->buffer_ptr = c->pb_buffer;
@@ -2723,7 +2723,7 @@ static int http_receive_data(HTTPContext *c)
 
             pb = avio_alloc_context(c->buffer, c->buffer_end - c->buffer,
                                     0, NULL, NULL, NULL, NULL);
-            pb->is_streamed = 1;
+            pb->seekable = 0;
 
             if (av_open_input_stream(&s, pb, c->stream->feed_filename, fmt_in, NULL) < 0) {
                 av_free(pb);
diff --git a/libavformat/aiffdec.c b/libavformat/aiffdec.c
index c3ad44e6df..8678f9bb9b 100644
--- a/libavformat/aiffdec.c
+++ b/libavformat/aiffdec.c
@@ -238,7 +238,7 @@ static int aiff_read_header(AVFormatContext *s,
             offset += avio_tell(pb);    /* Compute absolute data offset */
             if (st->codec->block_align)    /* Assume COMM already parsed */
                 goto got_sound;
-            if (url_is_streamed(pb)) {
+            if (!pb->seekable) {
                 av_log(s, AV_LOG_ERROR, "file is not seekable\n");
                 return -1;
             }
diff --git a/libavformat/aiffenc.c b/libavformat/aiffenc.c
index c61150987f..3bdb4f4f8c 100644
--- a/libavformat/aiffenc.c
+++ b/libavformat/aiffenc.c
@@ -124,7 +124,7 @@ static int aiff_write_trailer(AVFormatContext *s)
         end_size++;
     }
 
-    if (!url_is_streamed(s->pb)) {
+    if (s->pb->seekable) {
         /* File length */
         avio_seek(pb, aiff->form, SEEK_SET);
         avio_wb32(pb, file_size - aiff->form - 4);
diff --git a/libavformat/ape.c b/libavformat/ape.c
index 5aac00c56a..956036d5a8 100644
--- a/libavformat/ape.c
+++ b/libavformat/ape.c
@@ -296,7 +296,7 @@ static int ape_read_header(AVFormatContext * s, AVFormatParameters * ap)
     ape_dumpinfo(s, ape);
 
     /* try to read APE tags */
-    if (!url_is_streamed(pb)) {
+    if (pb->seekable) {
         ff_ape_parse_tag(s);
         avio_seek(pb, 0, SEEK_SET);
     }
diff --git a/libavformat/asfenc.c b/libavformat/asfenc.c
index 677c6882bf..c029c0e163 100644
--- a/libavformat/asfenc.c
+++ b/libavformat/asfenc.c
@@ -347,7 +347,7 @@ static int asf_write_header1(AVFormatContext *s, int64_t file_size, int64_t data
     avio_wl64(pb, duration); /* end time stamp (in 100ns units) */
     avio_wl64(pb, asf->duration); /* duration (in 100ns units) */
     avio_wl64(pb, PREROLL_TIME); /* start time stamp */
-    avio_wl32(pb, (asf->is_streamed || url_is_streamed(pb)) ? 3 : 2); /* ??? */
+    avio_wl32(pb, (asf->is_streamed || !pb->seekable ) ? 3 : 2); /* ??? */
     avio_wl32(pb, s->packet_size); /* packet size */
     avio_wl32(pb, s->packet_size); /* packet size */
     avio_wl32(pb, bit_rate); /* Nominal data rate in bps */
@@ -866,7 +866,7 @@ static int asf_write_trailer(AVFormatContext *s)
     }
     avio_flush(s->pb);
 
-    if (asf->is_streamed || url_is_streamed(s->pb)) {
+    if (asf->is_streamed || !s->pb->seekable) {
         put_chunk(s, 0x4524, 0, 0); /* end of stream */
     } else {
         /* rewrite an updated header */
diff --git a/libavformat/au.c b/libavformat/au.c
index f70f47ab39..6cffe1c1ce 100644
--- a/libavformat/au.c
+++ b/libavformat/au.c
@@ -91,7 +91,7 @@ static int au_write_trailer(AVFormatContext *s)
     AVIOContext *pb = s->pb;
     int64_t file_size;
 
-    if (!url_is_streamed(s->pb)) {
+    if (s->pb->seekable) {
 
         /* update file size */
         file_size = avio_tell(pb);
diff --git a/libavformat/avidec.c b/libavformat/avidec.c
index 43ced28001..ae8d32045f 100644
--- a/libavformat/avidec.c
+++ b/libavformat/avidec.c
@@ -665,7 +665,7 @@ static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
             break;
         case MKTAG('i', 'n', 'd', 'x'):
             i= avio_tell(pb);
-            if(!url_is_streamed(pb) && !(s->flags & AVFMT_FLAG_IGNIDX)){
+            if(pb->seekable && !(s->flags & AVFMT_FLAG_IGNIDX)){
                 read_braindead_odml_indx(s, 0);
             }
             avio_seek(pb, i+size, SEEK_SET);
@@ -721,7 +721,7 @@ static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
         return -1;
     }
 
-    if(!avi->index_loaded && !url_is_streamed(pb))
+    if(!avi->index_loaded && pb->seekable)
         avi_load_index(s);
     avi->index_loaded = 1;
     avi->non_interleaved |= guess_ni_flag(s);
diff --git a/libavformat/avienc.c b/libavformat/avienc.c
index 6b528c8f25..1b6f64527e 100644
--- a/libavformat/avienc.c
+++ b/libavformat/avienc.c
@@ -197,7 +197,7 @@ static int avi_write_header(AVFormatContext *s)
     }
     avio_wl32(pb, bitrate / 8); /* XXX: not quite exact */
     avio_wl32(pb, 0); /* padding */
-    if (url_is_streamed(pb))
+    if (!pb->seekable)
         avio_wl32(pb, AVIF_TRUSTCKTYPE | AVIF_ISINTERLEAVED); /* flags */
     else
         avio_wl32(pb, AVIF_TRUSTCKTYPE | AVIF_HASINDEX | AVIF_ISINTERLEAVED); /* flags */
@@ -259,7 +259,7 @@ static int avi_write_header(AVFormatContext *s)
 
         avio_wl32(pb, 0); /* start */
         avist->frames_hdr_strm = avio_tell(pb); /* remember this offset to fill later */
-        if (url_is_streamed(pb))
+        if (!pb->seekable)
             avio_wl32(pb, AVI_MAX_RIFF_SIZE); /* FIXME: this may be broken, but who cares */
         else
             avio_wl32(pb, 0); /* length, XXX: filled later */
@@ -303,7 +303,7 @@ static int avi_write_header(AVFormatContext *s)
         }
       }
 
-        if (!url_is_streamed(pb)) {
+        if (pb->seekable) {
             unsigned char tag[5];
             int j;
 
@@ -362,7 +362,7 @@ static int avi_write_header(AVFormatContext *s)
         ff_end_tag(pb, list2);
     }
 
-    if (!url_is_streamed(pb)) {
+    if (pb->seekable) {
         /* AVI could become an OpenDML one, if it grows beyond 2Gb range */
         avi->odml_list = ff_start_tag(pb, "JUNK");
         ffio_wfourcc(pb, "odml");
@@ -406,7 +406,7 @@ static int avi_write_ix(AVFormatContext *s)
     char ix_tag[] = "ix00";
     int i, j;
 
-    assert(!url_is_streamed(pb));
+    assert(pb->seekable);
 
     if (avi->riff_id > AVI_MASTER_INDEX_SIZE)
         return -1;
@@ -464,7 +464,7 @@ static int avi_write_idx1(AVFormatContext *s)
     int i;
     char tag[5];
 
-    if (!url_is_streamed(pb)) {
+    if (pb->seekable) {
         AVIStream *avist;
         AVIIentry* ie = 0, *tie;
         int empty, stream_id = -1;
@@ -532,7 +532,7 @@ static int avi_write_packet(AVFormatContext *s, AVPacket *pkt)
     avist->packet_count++;
 
     // Make sure to put an OpenDML chunk when the file size exceeds the limits
-    if (!url_is_streamed(pb) &&
+    if (pb->seekable &&
         (avio_tell(pb) - avi->riff_start > AVI_MAX_RIFF_SIZE)) {
 
         avi_write_ix(s);
@@ -552,7 +552,7 @@ static int avi_write_packet(AVFormatContext *s, AVPacket *pkt)
        avist->audio_strm_length += size;
     }
 
-    if (!url_is_streamed(s->pb)) {
+    if (s->pb->seekable) {
         AVIIndex* idx = &avist->indexes;
         int cl = idx->entry / AVI_INDEX_CLUSTER_SIZE;
         int id = idx->entry % AVI_INDEX_CLUSTER_SIZE;
@@ -590,7 +590,7 @@ static int avi_write_trailer(AVFormatContext *s)
     int i, j, n, nb_frames;
     int64_t file_size;
 
-    if (!url_is_streamed(pb)){
+    if (pb->seekable){
         if (avi->riff_id == 1) {
             ff_end_tag(pb, avi->movi_list);
             res = avi_write_idx1(s);
diff --git a/libavformat/avio.h b/libavformat/avio.h
index 7c2726f656..80446b4808 100644
--- a/libavformat/avio.h
+++ b/libavformat/avio.h
@@ -332,6 +332,8 @@ attribute_deprecated int av_register_protocol(URLProtocol *protocol);
  */
 int av_register_protocol2(URLProtocol *protocol, int size);
 
+#define AVIO_SEEKABLE_NORMAL 0x0001 /**< Seeking works like for a local file */
+
 /**
  * Bytestream IO Context.
  * New fields can be added to the end with minor version bumps.
@@ -351,7 +353,9 @@ typedef struct {
     int must_flush; /**< true if the next seek should flush */
     int eof_reached; /**< true if eof reached */
     int write_flag;  /**< true if open for writing */
-    int is_streamed;
+#if FF_API_OLD_AVIO
+    attribute_deprecated int is_streamed;
+#endif
     int max_packet_size;
     unsigned long checksum;
     unsigned char *checksum_ptr;
@@ -360,6 +364,10 @@ typedef struct {
     int (*read_pause)(void *opaque, int pause);
     int64_t (*read_seek)(void *opaque, int stream_index,
                          int64_t timestamp, int flags);
+    /**
+     * A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
+     */
+    int seekable;
 } AVIOContext;
 
 #if FF_API_OLD_AVIO
@@ -604,10 +612,15 @@ unsigned int avio_rb24(AVIOContext *s);
 unsigned int avio_rb32(AVIOContext *s);
 uint64_t     avio_rb64(AVIOContext *s);
 
-static inline int url_is_streamed(AVIOContext *s)
+#if FF_API_OLD_AVIO
+/**
+ * @deprecated Use AVIOContext.seekable field directly.
+ */
+attribute_deprecated static inline int url_is_streamed(AVIOContext *s)
 {
-    return s->is_streamed;
+    return !s->seekable;
 }
+#endif
 
 /**
  * Create and initialize a AVIOContext for accessing the
diff --git a/libavformat/aviobuf.c b/libavformat/aviobuf.c
index 2e7ee15b2a..dd997d73e2 100644
--- a/libavformat/aviobuf.c
+++ b/libavformat/aviobuf.c
@@ -62,7 +62,10 @@ int ffio_init_context(AVIOContext *s,
     s->must_flush = 0;
     s->eof_reached = 0;
     s->error = 0;
+#if FF_API_OLD_AVIO
     s->is_streamed = 0;
+#endif
+    s->seekable = AVIO_SEEKABLE_NORMAL;
     s->max_packet_size = 0;
     s->update_checksum= NULL;
     if(!read_packet && !write_flag){
@@ -202,7 +205,7 @@ int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
         offset1 >= 0 && offset1 <= (s->buf_end - s->buffer)) {
         /* can do the seek inside the buffer */
         s->buf_ptr = s->buffer + offset1;
-    } else if ((s->is_streamed ||
+    } else if ((!s->seekable ||
                offset1 <= s->buf_end + SHORT_SEEK_THRESHOLD - s->buffer) &&
                !s->write_flag && offset1 >= 0 &&
               (whence != SEEK_END || force)) {
@@ -831,7 +834,10 @@ int url_fdopen(AVIOContext **s, URLContext *h)
         av_freep(s);
         return AVERROR(EIO);
     }
+#if FF_API_OLD_AVIO
     (*s)->is_streamed = h->is_streamed;
+#endif
+    (*s)->seekable = h->is_streamed ? 0 : AVIO_SEEKABLE_NORMAL;
     (*s)->max_packet_size = max_packet_size;
     if(h->prot) {
         (*s)->read_pause = (int (*)(void *, int))h->prot->url_read_pause;
diff --git a/libavformat/bink.c b/libavformat/bink.c
index 1103aca873..76b457c21b 100644
--- a/libavformat/bink.c
+++ b/libavformat/bink.c
@@ -247,7 +247,7 @@ static int read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, in
     BinkDemuxContext *bink = s->priv_data;
     AVStream *vst = s->streams[0];
 
-    if (url_is_streamed(s->pb))
+    if (!s->pb->seekable)
         return -1;
 
     /* seek to the first frame */
diff --git a/libavformat/cafdec.c b/libavformat/cafdec.c
index 45a6629fc1..c720c34375 100644
--- a/libavformat/cafdec.c
+++ b/libavformat/cafdec.c
@@ -223,7 +223,7 @@ static int read_header(AVFormatContext *s,
 
         /* stop at data chunk if seeking is not supported or
            data chunk size is unknown */
-        if (found_data && (caf->data_size < 0 || url_is_streamed(pb)))
+        if (found_data && (caf->data_size < 0 || !pb->seekable))
             break;
 
         tag  = avio_rb32(pb);
@@ -236,7 +236,7 @@ static int read_header(AVFormatContext *s,
             avio_skip(pb, 4); /* edit count */
             caf->data_start = avio_tell(pb);
             caf->data_size  = size < 0 ? -1 : size - 4;
-            if (caf->data_size > 0 && !url_is_streamed(pb))
+            if (caf->data_size > 0 && pb->seekable)
                 avio_skip(pb, caf->data_size);
             found_data = 1;
             break;
diff --git a/libavformat/ffmdec.c b/libavformat/ffmdec.c
index edea965034..6cd2b51392 100644
--- a/libavformat/ffmdec.c
+++ b/libavformat/ffmdec.c
@@ -281,7 +281,7 @@ static int ffm_read_header(AVFormatContext *s, AVFormatParameters *ap)
         goto fail;
     ffm->write_index = avio_rb64(pb);
     /* get also filesize */
-    if (!url_is_streamed(pb)) {
+    if (pb->seekable) {
         ffm->file_size = avio_size(pb);
         if (ffm->write_index)
             adjust_write_index(s);
diff --git a/libavformat/filmstripdec.c b/libavformat/filmstripdec.c
index 9af8e745d6..095bf9e809 100644
--- a/libavformat/filmstripdec.c
+++ b/libavformat/filmstripdec.c
@@ -40,7 +40,7 @@ static int read_header(AVFormatContext *s,
     AVIOContext *pb = s->pb;
     AVStream *st;
 
-    if (url_is_streamed(s->pb))
+    if (!s->pb->seekable)
         return AVERROR(EIO);
 
     avio_seek(pb, avio_size(pb) - 36, SEEK_SET);
diff --git a/libavformat/flacenc.c b/libavformat/flacenc.c
index 35c796bdca..38c3265d0c 100644
--- a/libavformat/flacenc.c
+++ b/libavformat/flacenc.c
@@ -98,7 +98,7 @@ static int flac_write_trailer(struct AVFormatContext *s)
     if (!ff_flac_is_extradata_valid(s->streams[0]->codec, &format, &streaminfo))
         return -1;
 
-    if (!url_is_streamed(pb)) {
+    if (pb->seekable) {
         /* rewrite the STREAMINFO header block data */
         file_size = avio_tell(pb);
         avio_seek(pb, 8, SEEK_SET);
diff --git a/libavformat/flvdec.c b/libavformat/flvdec.c
index 972b4d95dd..ef26b05b3b 100644
--- a/libavformat/flvdec.c
+++ b/libavformat/flvdec.c
@@ -437,7 +437,7 @@ static int flv_read_packet(AVFormatContext *s, AVPacket *pkt)
  }
 
     // if not streamed and no duration from metadata then seek to end to find the duration from the timestamps
-    if(!url_is_streamed(s->pb) && (!s->duration || s->duration==AV_NOPTS_VALUE)){
+    if(s->pb->seekable && (!s->duration || s->duration==AV_NOPTS_VALUE)){
         int size;
         const int64_t pos= avio_tell(s->pb);
         const int64_t fsize= avio_size(s->pb);
@@ -539,7 +539,7 @@ static int flv_read_seek2(AVFormatContext *s, int stream_index,
 
     if (ts - min_ts > (uint64_t)(max_ts - ts)) flags |= AVSEEK_FLAG_BACKWARD;
 
-    if (url_is_streamed(s->pb)) {
+    if (!s->pb->seekable) {
         if (stream_index < 0) {
             stream_index = av_find_default_stream_index(s);
             if (stream_index < 0)
diff --git a/libavformat/gxfenc.c b/libavformat/gxfenc.c
index a4dffda1ce..585e0eefaa 100644
--- a/libavformat/gxfenc.c
+++ b/libavformat/gxfenc.c
@@ -634,7 +634,7 @@ static int gxf_write_header(AVFormatContext *s)
     uint8_t tracks[255] = {0};
     int i, media_info = 0;
 
-    if (url_is_streamed(pb)) {
+    if (!pb->seekable) {
         av_log(s, AV_LOG_ERROR, "gxf muxer does not support streamed output, patch welcome");
         return -1;
     }
diff --git a/libavformat/id3v1.c b/libavformat/id3v1.c
index 1f1df9cd02..d296ebbe57 100644
--- a/libavformat/id3v1.c
+++ b/libavformat/id3v1.c
@@ -229,7 +229,7 @@ void ff_id3v1_read(AVFormatContext *s)
     uint8_t buf[ID3v1_TAG_SIZE];
     int64_t filesize, position = avio_tell(s->pb);
 
-    if (!url_is_streamed(s->pb)) {
+    if (s->pb->seekable) {
         /* XXX: change that */
         filesize = avio_size(s->pb);
         if (filesize > 128) {
diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
index 61a77abdf8..fb8c3e9874 100644
--- a/libavformat/matroskadec.c
+++ b/libavformat/matroskadec.c
@@ -1117,7 +1117,7 @@ static void matroska_execute_seekhead(MatroskaDemuxContext *matroska)
     int i;
 
     // we should not do any seeking in the streaming case
-    if (url_is_streamed(matroska->ctx->pb) ||
+    if (!matroska->ctx->pb->seekable ||
         (matroska->ctx->flags & AVFMT_FLAG_IGNIDX))
         return;
 
diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
index 4f9bf0a723..a06891d8b8 100644
--- a/libavformat/matroskaenc.c
+++ b/libavformat/matroskaenc.c
@@ -848,7 +848,7 @@ static int mkv_write_header(AVFormatContext *s)
         if (ret < 0) return ret;
     }
 
-    if (url_is_streamed(s->pb))
+    if (!s->pb->seekable)
         mkv_write_seekhead(pb, mkv->main_seekhead);
 
     mkv->cues = mkv_start_cues(mkv->segment_offset);
@@ -1024,7 +1024,7 @@ static int mkv_write_packet_internal(AVFormatContext *s, AVPacket *pkt)
         return AVERROR(EINVAL);
     }
 
-    if (url_is_streamed(s->pb)) {
+    if (!s->pb->seekable) {
         if (!mkv->dyn_bc)
             url_open_dyn_buf(&mkv->dyn_bc);
         pb = mkv->dyn_bc;
@@ -1076,16 +1076,16 @@ static int mkv_copy_packet(MatroskaMuxContext *mkv, const AVPacket *pkt)
 static int mkv_write_packet(AVFormatContext *s, AVPacket *pkt)
 {
     MatroskaMuxContext *mkv = s->priv_data;
-    AVIOContext *pb = url_is_streamed(s->pb) ? mkv->dyn_bc : s->pb;
+    AVIOContext *pb = s->pb->seekable ? s->pb : mkv->dyn_bc;
     AVCodecContext *codec = s->streams[pkt->stream_index]->codec;
     int ret, keyframe = !!(pkt->flags & AV_PKT_FLAG_KEY);
     int64_t ts = mkv->tracks[pkt->stream_index].write_dts ? pkt->dts : pkt->pts;
-    int cluster_size = avio_tell(pb) - (url_is_streamed(s->pb) ? 0 : mkv->cluster_pos);
+    int cluster_size = avio_tell(pb) - (s->pb->seekable ? mkv->cluster_pos : 0);
 
     // start a new cluster every 5 MB or 5 sec, or 32k / 1 sec for streaming or
     // after 4k and on a keyframe
     if (mkv->cluster_pos &&
-        ((url_is_streamed(s->pb) && (cluster_size > 32*1024 || ts > mkv->cluster_pts + 1000))
+        ((!s->pb->seekable && (cluster_size > 32*1024 || ts > mkv->cluster_pts + 1000))
          ||                      cluster_size > 5*1024*1024 || ts > mkv->cluster_pts + 5000
          || (codec->codec_type == AVMEDIA_TYPE_VIDEO && keyframe && cluster_size > 4*1024))) {
         av_log(s, AV_LOG_DEBUG, "Starting new cluster at offset %" PRIu64
@@ -1139,7 +1139,7 @@ static int mkv_write_trailer(AVFormatContext *s)
         end_ebml_master(pb, mkv->cluster);
     }
 
-    if (!url_is_streamed(pb)) {
+    if (pb->seekable) {
         cuespos = mkv_write_cues(pb, mkv->cues, s->nb_streams);
 
         ret = mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_CUES    , cuespos);
diff --git a/libavformat/mmf.c b/libavformat/mmf.c
index d4247544c2..ec99c2d0dd 100644
--- a/libavformat/mmf.c
+++ b/libavformat/mmf.c
@@ -133,7 +133,7 @@ static int mmf_write_trailer(AVFormatContext *s)
     int64_t pos, size;
     int gatetime;
 
-    if (!url_is_streamed(s->pb)) {
+    if (s->pb->seekable) {
         /* Fill in length fields */
         end_tag_be(pb, mmf->awapos);
         end_tag_be(pb, mmf->atrpos);
diff --git a/libavformat/mov.c b/libavformat/mov.c
index b57c1aab1c..2194dc929a 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -304,7 +304,7 @@ static int mov_read_default(MOVContext *c, AVIOContext *pb, MOVAtom atom)
             if (err < 0)
                 return err;
             if (c->found_moov && c->found_mdat &&
-                (url_is_streamed(pb) || start_pos + a.size == avio_size(pb)))
+                (!pb->seekable || start_pos + a.size == avio_size(pb)))
                 return 0;
             left = a.size - avio_tell(pb) + start_pos;
             if (left > 0) /* skip garbage at atom end */
@@ -2354,7 +2354,7 @@ static int mov_read_header(AVFormatContext *s, AVFormatParameters *ap)
 
     mov->fc = s;
     /* .mov and .mp4 aren't streamable anyway (only progressive download if moov is before mdat) */
-    if(!url_is_streamed(pb))
+    if(pb->seekable)
         atom.size = avio_size(pb);
     else
         atom.size = INT64_MAX;
@@ -2370,7 +2370,7 @@ static int mov_read_header(AVFormatContext *s, AVFormatParameters *ap)
     }
     av_dlog(mov->fc, "on_parse_exit_offset=%lld\n", avio_tell(pb));
 
-    if (!url_is_streamed(pb) && mov->chapter_track > 0)
+    if (pb->seekable && mov->chapter_track > 0)
         mov_read_chapters(s);
 
     return 0;
@@ -2388,8 +2388,8 @@ static AVIndexEntry *mov_find_next_sample(AVFormatContext *s, AVStream **st)
             AVIndexEntry *current_sample = &avst->index_entries[msc->current_sample];
             int64_t dts = av_rescale(current_sample->timestamp, AV_TIME_BASE, msc->time_scale);
             av_dlog(s, "stream %d, sample %d, dts %"PRId64"\n", i, msc->current_sample, dts);
-            if (!sample || (url_is_streamed(s->pb) && current_sample->pos < sample->pos) ||
-                (!url_is_streamed(s->pb) &&
+            if (!sample || (!s->pb->seekable && current_sample->pos < sample->pos) ||
+                (s->pb->seekable &&
                  ((msc->pb != s->pb && dts < best_dts) || (msc->pb == s->pb &&
                  ((FFABS(best_dts - dts) <= AV_TIME_BASE && current_sample->pos < sample->pos) ||
                   (FFABS(best_dts - dts) > AV_TIME_BASE && dts < best_dts)))))) {
@@ -2413,7 +2413,7 @@ static int mov_read_packet(AVFormatContext *s, AVPacket *pkt)
     sample = mov_find_next_sample(s, &st);
     if (!sample) {
         mov->found_mdat = 0;
-        if (!url_is_streamed(s->pb) ||
+        if (s->pb->seekable||
             mov_read_default(mov, s->pb, (MOVAtom){ AV_RL32("root"), INT64_MAX }) < 0 ||
             s->pb->eof_reached)
             return AVERROR_EOF;
diff --git a/libavformat/movenc.c b/libavformat/movenc.c
index 3191e67479..0c5de80d3c 100644
--- a/libavformat/movenc.c
+++ b/libavformat/movenc.c
@@ -1955,7 +1955,7 @@ int ff_mov_write_packet(AVFormatContext *s, AVPacket *pkt)
     unsigned int samplesInChunk = 0;
     int size= pkt->size;
 
-    if (url_is_streamed(s->pb)) return 0; /* Can't handle that */
+    if (!s->pb->seekable) return 0; /* Can't handle that */
     if (!size) return 0; /* Discard 0 sized packets */
 
     if (enc->codec_id == CODEC_ID_AMR_NB) {
@@ -2090,7 +2090,7 @@ static int mov_write_header(AVFormatContext *s)
     MOVMuxContext *mov = s->priv_data;
     int i, hint_track = 0;
 
-    if (url_is_streamed(s->pb)) {
+    if (!s->pb->seekable) {
         av_log(s, AV_LOG_ERROR, "muxer does not support non seekable output\n");
         return -1;
     }
diff --git a/libavformat/mpc.c b/libavformat/mpc.c
index baee5775af..07c22990f6 100644
--- a/libavformat/mpc.c
+++ b/libavformat/mpc.c
@@ -93,7 +93,7 @@ static int mpc_read_header(AVFormatContext *s, AVFormatParameters *ap)
     st->duration = c->fcount;
 
     /* try to read APE tags */
-    if (!url_is_streamed(s->pb)) {
+    if (s->pb->seekable) {
         int64_t pos = avio_tell(s->pb);
         ff_ape_parse_tag(s);
         if (!av_metadata_get(s->metadata, "", NULL, AV_METADATA_IGNORE_SUFFIX))
diff --git a/libavformat/mpeg.c b/libavformat/mpeg.c
index 4a0c5f1400..68b685cc29 100644
--- a/libavformat/mpeg.c
+++ b/libavformat/mpeg.c
@@ -402,7 +402,7 @@ static int mpegps_read_pes_header(AVFormatContext *s,
         int i;
         for(i=0; i<s->nb_streams; i++){
             if(startcode == s->streams[i]->id &&
-               !url_is_streamed(s->pb) /* index useless on streams anyway */) {
+               s->pb->seekable /* index useless on streams anyway */) {
                 ff_reduce_index(s, i);
                 av_add_index_entry(s->streams[i], *ppos, dts, 0, 0, AVINDEX_KEYFRAME /* FIXME keyframe? */);
             }
diff --git a/libavformat/mxfenc.c b/libavformat/mxfenc.c
index f9b662555a..44052a0610 100644
--- a/libavformat/mxfenc.c
+++ b/libavformat/mxfenc.c
@@ -1784,7 +1784,7 @@ static int mxf_write_footer(AVFormatContext *s)
     mxf_write_klv_fill(s);
     mxf_write_random_index_pack(s);
 
-    if (!url_is_streamed(s->pb)) {
+    if (s->pb->seekable) {
         avio_seek(pb, 0, SEEK_SET);
         if (mxf->edit_unit_byte_count) {
             mxf_write_partition(s, 1, 2, header_closed_partition_key, 1);
diff --git a/libavformat/nutdec.c b/libavformat/nutdec.c
index ac17e86123..d3804f2993 100644
--- a/libavformat/nutdec.c
+++ b/libavformat/nutdec.c
@@ -653,7 +653,7 @@ static int nut_read_header(AVFormatContext *s, AVFormatParameters *ap)
 
     s->data_offset= pos-8;
 
-    if(!url_is_streamed(bc)){
+    if(bc->seekable){
         int64_t orig_pos= avio_tell(bc);
         find_and_decode_index(nut);
         avio_seek(bc, orig_pos, SEEK_SET);
diff --git a/libavformat/oggdec.c b/libavformat/oggdec.c
index 76ef19ada3..cd866d4108 100644
--- a/libavformat/oggdec.c
+++ b/libavformat/oggdec.c
@@ -455,7 +455,7 @@ ogg_get_length (AVFormatContext * s)
     int i;
     int64_t size, end;
 
-    if(url_is_streamed(s->pb))
+    if(!s->pb->seekable)
         return 0;
 
 // already set
diff --git a/libavformat/r3d.c b/libavformat/r3d.c
index 60ac169a9c..e815fda930 100644
--- a/libavformat/r3d.c
+++ b/libavformat/r3d.c
@@ -177,7 +177,7 @@ static int r3d_read_header(AVFormatContext *s, AVFormatParameters *ap)
 
     s->data_offset = avio_tell(s->pb);
     av_dlog(s, "data offset %#llx\n", s->data_offset);
-    if (url_is_streamed(s->pb))
+    if (!s->pb->seekable)
         return 0;
     // find REOB/REOF/REOS to load index
     avio_seek(s->pb, avio_size(s->pb)-48-8, SEEK_SET);
diff --git a/libavformat/rmdec.c b/libavformat/rmdec.c
index a68af18bdd..bcf55fddfa 100644
--- a/libavformat/rmdec.c
+++ b/libavformat/rmdec.c
@@ -481,7 +481,7 @@ static int rm_read_header(AVFormatContext *s, AVFormatParameters *ap)
 
     if (!data_off)
         data_off = avio_tell(pb) - 18;
-    if (indx_off && !url_is_streamed(pb) && !(s->flags & AVFMT_FLAG_IGNIDX) &&
+    if (indx_off && pb->seekable && !(s->flags & AVFMT_FLAG_IGNIDX) &&
         avio_seek(pb, indx_off, SEEK_SET) >= 0) {
         rm_read_index(s);
         avio_seek(pb, data_off + 18, SEEK_SET);
diff --git a/libavformat/rmenc.c b/libavformat/rmenc.c
index 6f8b0937f3..d64040c1a2 100644
--- a/libavformat/rmenc.c
+++ b/libavformat/rmenc.c
@@ -118,7 +118,7 @@ static int rv10_write_header(AVFormatContext *ctx,
     avio_wb32(s, 0);           /* data offset : will be patched after */
     avio_wb16(s, ctx->nb_streams);    /* num streams */
     flags = 1 | 2; /* save allowed & perfect play */
-    if (url_is_streamed(s))
+    if (!s->seekable)
         flags |= 4; /* live broadcast */
     avio_wb16(s, flags);
 
@@ -170,7 +170,7 @@ static int rv10_write_header(AVFormatContext *ctx,
         avio_wb32(s, 0);           /* start time */
         avio_wb32(s, BUFFER_DURATION);           /* preroll */
         /* duration */
-        if (url_is_streamed(s) || !stream->total_frames)
+        if (!s->seekable || !stream->total_frames)
             avio_wb32(s, (int)(3600 * 1000));
         else
             avio_wb32(s, (int)(stream->total_frames * 1000 / stream->frame_rate));
@@ -434,7 +434,7 @@ static int rm_write_trailer(AVFormatContext *s)
     int data_size, index_pos, i;
     AVIOContext *pb = s->pb;
 
-    if (!url_is_streamed(s->pb)) {
+    if (s->pb->seekable) {
         /* end of file: finish to write header */
         index_pos = avio_tell(pb);
         data_size = index_pos - rm->data_pos;
diff --git a/libavformat/rsoenc.c b/libavformat/rsoenc.c
index cfa54f1142..338ecf0173 100644
--- a/libavformat/rsoenc.c
+++ b/libavformat/rsoenc.c
@@ -38,7 +38,7 @@ static int rso_write_header(AVFormatContext *s)
         return AVERROR_INVALIDDATA;
     }
 
-    if (url_is_streamed(s->pb)) {
+    if (!s->pb->seekable) {
         av_log(s, AV_LOG_ERROR, "muxer does not support non seekable output\n");
         return AVERROR_INVALIDDATA;
     }
diff --git a/libavformat/soxenc.c b/libavformat/soxenc.c
index a2e496e8c2..cb71d73e9f 100644
--- a/libavformat/soxenc.c
+++ b/libavformat/soxenc.c
@@ -96,7 +96,7 @@ static int sox_write_trailer(AVFormatContext *s)
     AVIOContext *pb = s->pb;
     AVCodecContext *enc = s->streams[0]->codec;
 
-    if (!url_is_streamed(s->pb)) {
+    if (s->pb->seekable) {
         /* update number of samples */
         int64_t file_size = avio_tell(pb);
         int64_t num_samples = (file_size - sox->header_size - 4LL) >> 2LL;
diff --git a/libavformat/swfenc.c b/libavformat/swfenc.c
index 96e0c49362..4c5c3155ab 100644
--- a/libavformat/swfenc.c
+++ b/libavformat/swfenc.c
@@ -492,7 +492,7 @@ static int swf_write_trailer(AVFormatContext *s)
     avio_flush(s->pb);
 
     /* patch file size and number of frames if not streamed */
-    if (!url_is_streamed(s->pb) && video_enc) {
+    if (s->pb->seekable && video_enc) {
         file_size = avio_tell(pb);
         avio_seek(pb, 4, SEEK_SET);
         avio_wl32(pb, file_size);
diff --git a/libavformat/tty.c b/libavformat/tty.c
index 821f2a6b0e..ea8d0c7ece 100644
--- a/libavformat/tty.c
+++ b/libavformat/tty.c
@@ -88,7 +88,7 @@ static int read_header(AVFormatContext *avctx,
     /* simulate tty display speed */
     s->chars_per_frame = FFMAX(av_q2d(st->time_base) * (ap->sample_rate ? ap->sample_rate : LINE_RATE), 1);
 
-    if (!url_is_streamed(avctx->pb)) {
+    if (avctx->pb->seekable) {
         s->fsize = avio_size(avctx->pb);
         st->duration = (s->fsize + s->chars_per_frame - 1) / s->chars_per_frame;
 
diff --git a/libavformat/utils.c b/libavformat/utils.c
index ca0bf7ec05..31eddec12a 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -2019,7 +2019,7 @@ static void av_estimate_timings(AVFormatContext *ic, int64_t old_offset)
 
     if ((!strcmp(ic->iformat->name, "mpeg") ||
          !strcmp(ic->iformat->name, "mpegts")) &&
-        file_size && !url_is_streamed(ic->pb)) {
+        file_size && ic->pb->seekable) {
         /* get accurate estimate from the PTSes */
         av_estimate_timings_from_pts(ic, old_offset);
     } else if (av_has_duration(ic)) {
diff --git a/libavformat/vc1testenc.c b/libavformat/vc1testenc.c
index bf6144849e..2b0728d248 100644
--- a/libavformat/vc1testenc.c
+++ b/libavformat/vc1testenc.c
@@ -73,7 +73,7 @@ static int vc1test_write_trailer(AVFormatContext *s)
     RCVContext *ctx = s->priv_data;
     AVIOContext *pb = s->pb;
 
-    if (!url_is_streamed(s->pb)) {
+    if (s->pb->seekable) {
         avio_seek(pb, 0, SEEK_SET);
         avio_wl24(pb, ctx->frames);
         avio_flush(pb);
diff --git a/libavformat/vocdec.c b/libavformat/vocdec.c
index 48e3d10c0b..eaa2f25492 100644
--- a/libavformat/vocdec.c
+++ b/libavformat/vocdec.c
@@ -78,7 +78,7 @@ voc_get_packet(AVFormatContext *s, AVPacket *pkt, AVStream *st, int max_size)
             return AVERROR(EIO);
         voc->remaining_size = avio_rl24(pb);
         if (!voc->remaining_size) {
-            if (url_is_streamed(s->pb))
+            if (!s->pb->seekable)
                 return AVERROR(EIO);
             voc->remaining_size = avio_size(pb) - avio_tell(pb);
         }
diff --git a/libavformat/wav.c b/libavformat/wav.c
index 6c1dcf5369..47685d466a 100644
--- a/libavformat/wav.c
+++ b/libavformat/wav.c
@@ -58,7 +58,7 @@ static int wav_write_header(AVFormatContext *s)
     ff_end_tag(pb, fmt);
 
     if (s->streams[0]->codec->codec_tag != 0x01 /* hence for all other than PCM */
-        && !url_is_streamed(s->pb)) {
+        && s->pb->seekable) {
         fact = ff_start_tag(pb, "fact");
         avio_wl32(pb, 0);
         ff_end_tag(pb, fact);
@@ -98,7 +98,7 @@ static int wav_write_trailer(AVFormatContext *s)
 
     avio_flush(pb);
 
-    if (!url_is_streamed(s->pb)) {
+    if (s->pb->seekable) {
         ff_end_tag(pb, wav->data);
 
         /* update file size */
diff --git a/libavformat/wv.c b/libavformat/wv.c
index f48db2364d..7106735041 100644
--- a/libavformat/wv.c
+++ b/libavformat/wv.c
@@ -121,7 +121,7 @@ static int wv_read_block_header(AVFormatContext *ctx, AVIOContext *pb, int appen
     }
     if((rate == -1 || !chan) && !wc->block_parsed){
         int64_t block_end = avio_tell(pb) + wc->blksize - 24;
-        if(url_is_streamed(pb)){
+        if(!pb->seekable){
             av_log(ctx, AV_LOG_ERROR, "Cannot determine additional parameters\n");
             return -1;
         }
@@ -223,7 +223,7 @@ static int wv_read_header(AVFormatContext *s,
     st->start_time = 0;
     st->duration = wc->samples;
 
-    if(!url_is_streamed(s->pb)) {
+    if(s->pb->seekable) {
         int64_t cur = avio_tell(s->pb);
         ff_ape_parse_tag(s);
         if(!av_metadata_get(s->metadata, "", NULL, AV_METADATA_IGNORE_SUFFIX))