X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavformat%2Foggdec.c;h=79aa98f83d3a9c5eed749e7c2ad090e4abf8a3a1;hb=f9cf91d8224eb9081e50b6cee55423ccb0bf9e90;hp=7eb98472651c48a870747e56749506d37c5d874c;hpb=bde15e74de442cebf61acc6cd598a13aca249030;p=ffmpeg

diff --git a/libavformat/oggdec.c b/libavformat/oggdec.c
index 7eb98472651..79aa98f83d3 100644
--- a/libavformat/oggdec.c
+++ b/libavformat/oggdec.c
@@ -2,10 +2,9 @@
  * Ogg bitstream support
  * Luca Barbato <lu_zero@gentoo.org>
  * Based on tcvp implementation
- *
  */
 
-/**
+/*
     Copyright (C) 2005  Michael Ahlberg, Måns Rullgård
 
     Permission is hereby granted, free of charge, to any person
@@ -27,45 +26,50 @@
     WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
     OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
     DEALINGS IN THE SOFTWARE.
-**/
+ */
 
 
 #include <stdio.h>
 #include "oggdec.h"
 #include "avformat.h"
+#include "internal.h"
+#include "vorbiscomment.h"
 
 #define MAX_PAGE_SIZE 65307
 #define DECODER_BUFFER_SIZE MAX_PAGE_SIZE
 
-static ogg_codec_t *ogg_codecs[] = {
-    &speex_codec,
-    &vorbis_codec,
-    &theora_codec,
-    &flac_codec,
-    &old_flac_codec,
-    &ogm_video_codec,
-    &ogm_audio_codec,
-    &ogm_text_codec,
-    &ogm_old_codec,
+static const struct ogg_codec * const ogg_codecs[] = {
+    &ff_skeleton_codec,
+    &ff_dirac_codec,
+    &ff_speex_codec,
+    &ff_vorbis_codec,
+    &ff_theora_codec,
+    &ff_flac_codec,
+    &ff_celt_codec,
+    &ff_old_dirac_codec,
+    &ff_old_flac_codec,
+    &ff_ogm_video_codec,
+    &ff_ogm_audio_codec,
+    &ff_ogm_text_codec,
+    &ff_ogm_old_codec,
     NULL
 };
 
 //FIXME We could avoid some structure duplication
-static int
-ogg_save (AVFormatContext * s)
+static int ogg_save(AVFormatContext *s)
 {
-    ogg_t *ogg = s->priv_data;
-    ogg_state_t *ost =
+    struct ogg *ogg = s->priv_data;
+    struct ogg_state *ost =
         av_malloc(sizeof (*ost) + (ogg->nstreams-1) * sizeof (*ogg->streams));
     int i;
-    ost->pos = url_ftell (s->pb);
+    ost->pos = avio_tell (s->pb);
     ost->curidx = ogg->curidx;
     ost->next = ogg->state;
     ost->nstreams = ogg->nstreams;
     memcpy(ost->streams, ogg->streams, ogg->nstreams * sizeof(*ogg->streams));
 
     for (i = 0; i < ogg->nstreams; i++){
-        ogg_stream_t *os = ogg->streams + i;
+        struct ogg_stream *os = ogg->streams + i;
         os->buf = av_malloc (os->bufsize);
         memset (os->buf, 0, os->bufsize);
         memcpy (os->buf, ost->streams[i].buf, os->bufpos);
@@ -76,12 +80,11 @@ ogg_save (AVFormatContext * s)
     return 0;
 }
 
-static int
-ogg_restore (AVFormatContext * s, int discard)
+static int ogg_restore(AVFormatContext *s, int discard)
 {
-    ogg_t *ogg = s->priv_data;
-    ByteIOContext *bc = s->pb;
-    ogg_state_t *ost = ogg->state;
+    struct ogg *ogg = s->priv_data;
+    AVIOContext *bc = s->pb;
+    struct ogg_state *ost = ogg->state;
     int i;
 
     if (!ost)
@@ -90,14 +93,24 @@ ogg_restore (AVFormatContext * s, int discard)
     ogg->state = ost->next;
 
     if (!discard){
+        struct ogg_stream *old_streams = ogg->streams;
+
         for (i = 0; i < ogg->nstreams; i++)
             av_free (ogg->streams[i].buf);
 
-        url_fseek (bc, ost->pos, SEEK_SET);
+        avio_seek (bc, ost->pos, SEEK_SET);
         ogg->curidx = ost->curidx;
         ogg->nstreams = ost->nstreams;
-        memcpy(ogg->streams, ost->streams,
-               ost->nstreams * sizeof(*ogg->streams));
+        ogg->streams = av_realloc (ogg->streams,
+                                   ogg->nstreams * sizeof (*ogg->streams));
+
+        if (ogg->streams) {
+            memcpy(ogg->streams, ost->streams,
+                   ost->nstreams * sizeof(*ogg->streams));
+        } else {
+            av_free(old_streams);
+            ogg->nstreams = 0;
+        }
     }
 
     av_free (ost);
@@ -105,20 +118,23 @@ ogg_restore (AVFormatContext * s, int discard)
     return 0;
 }
 
-static int
-ogg_reset (ogg_t * ogg)
+static int ogg_reset(struct ogg *ogg)
 {
     int i;
 
     for (i = 0; i < ogg->nstreams; i++){
-        ogg_stream_t *os = ogg->streams + i;
+        struct ogg_stream *os = ogg->streams + i;
         os->bufpos = 0;
         os->pstart = 0;
         os->psize = 0;
         os->granule = -1;
-        os->lastgp = -1;
+        os->lastpts = AV_NOPTS_VALUE;
+        os->lastdts = AV_NOPTS_VALUE;
+        os->sync_pos = -1;
+        os->page_pos = 0;
         os->nsegs = 0;
         os->segp = 0;
+        os->incomplete = 0;
     }
 
     ogg->curidx = -1;
@@ -126,8 +142,7 @@ ogg_reset (ogg_t * ogg)
     return 0;
 }
 
-static ogg_codec_t *
-ogg_find_codec (uint8_t * buf, int size)
+static const struct ogg_codec *ogg_find_codec(uint8_t *buf, int size)
 {
     int i;
 
@@ -139,26 +154,13 @@ ogg_find_codec (uint8_t * buf, int size)
     return NULL;
 }
 
-static int
-ogg_find_stream (ogg_t * ogg, int serial)
+static int ogg_new_stream(AVFormatContext *s, uint32_t serial, int new_avstream)
 {
-    int i;
 
-    for (i = 0; i < ogg->nstreams; i++)
-        if (ogg->streams[i].serial == serial)
-            return i;
-
-    return -1;
-}
-
-static int
-ogg_new_stream (AVFormatContext * s, uint32_t serial)
-{
-
-    ogg_t *ogg = s->priv_data;
+    struct ogg *ogg = s->priv_data;
     int idx = ogg->nstreams++;
     AVStream *st;
-    ogg_stream_t *os;
+    struct ogg_stream *os;
 
     ogg->streams = av_realloc (ogg->streams,
                                ogg->nstreams * sizeof (*ogg->streams));
@@ -169,19 +171,21 @@ ogg_new_stream (AVFormatContext * s, uint32_t serial)
     os->buf = av_malloc(os->bufsize);
     os->header = -1;
 
-    st = av_new_stream (s, idx);
-    if (!st)
-        return AVERROR(ENOMEM);
+    if (new_avstream) {
+        st = avformat_new_stream(s, NULL);
+        if (!st)
+            return AVERROR(ENOMEM);
 
-    av_set_pts_info(st, 64, 1, 1000000);
+        st->id = idx;
+        avpriv_set_pts_info(st, 64, 1, 1000000);
+    }
 
     return idx;
 }
 
-static int
-ogg_new_buf(ogg_t *ogg, int idx)
+static int ogg_new_buf(struct ogg *ogg, int idx)
 {
-    ogg_stream_t *os = ogg->streams + idx;
+    struct ogg_stream *os = ogg->streams + idx;
     uint8_t *nb = av_malloc(os->bufsize);
     int size = os->bufpos - os->pstart;
     if(os->buf){
@@ -195,24 +199,22 @@ ogg_new_buf(ogg_t *ogg, int idx)
     return 0;
 }
 
-static int
-ogg_read_page (AVFormatContext * s, int *str)
+static int ogg_read_page(AVFormatContext *s, int *str)
 {
-    ByteIOContext *bc = s->pb;
-    ogg_t *ogg = s->priv_data;
-    ogg_stream_t *os;
-    int i = 0;
+    AVIOContext *bc = s->pb;
+    struct ogg *ogg = s->priv_data;
+    struct ogg_stream *os;
+    int ret, i = 0;
     int flags, nsegs;
     uint64_t gp;
     uint32_t serial;
-    uint32_t seq;
-    uint32_t crc;
     int size, idx;
     uint8_t sync[4];
     int sp = 0;
 
-    if (get_buffer (bc, sync, 4) < 4)
-        return -1;
+    ret = avio_read(bc, sync, 4);
+    if (ret < 4)
+        return ret < 0 ? ret : AVERROR_EOF;
 
     do{
         int c;
@@ -222,41 +224,55 @@ ogg_read_page (AVFormatContext * s, int *str)
             sync[(sp + 2) & 3] == 'g' && sync[(sp + 3) & 3] == 'S')
             break;
 
-        c = url_fgetc (bc);
-        if (c < 0)
-            return -1;
+        c = avio_r8(bc);
+        if (bc->eof_reached)
+            return AVERROR_EOF;
         sync[sp++ & 3] = c;
     }while (i++ < MAX_PAGE_SIZE);
 
     if (i >= MAX_PAGE_SIZE){
         av_log (s, AV_LOG_INFO, "ogg, can't find sync word\n");
-        return -1;
+        return AVERROR_INVALIDDATA;
     }
 
-    if (url_fgetc (bc) != 0)      /* version */
-        return -1;
+    if (avio_r8(bc) != 0)      /* version */
+        return AVERROR_INVALIDDATA;
 
-    flags = url_fgetc (bc);
-    gp = get_le64 (bc);
-    serial = get_le32 (bc);
-    seq = get_le32 (bc);
-    crc = get_le32 (bc);
-    nsegs = url_fgetc (bc);
+    flags = avio_r8(bc);
+    gp = avio_rl64 (bc);
+    serial = avio_rl32 (bc);
+    avio_skip(bc, 8); /* seq, crc */
+    nsegs = avio_r8(bc);
 
     idx = ogg_find_stream (ogg, serial);
     if (idx < 0){
-        idx = ogg_new_stream (s, serial);
+        if (ogg->headers) {
+            int n;
+
+            for (n = 0; n < ogg->nstreams; n++) {
+                av_freep(&ogg->streams[n].buf);
+                if (!ogg->state || ogg->state->streams[n].private != ogg->streams[n].private)
+                    av_freep(&ogg->streams[n].private);
+            }
+            ogg->curidx   = -1;
+            ogg->nstreams = 0;
+            idx = ogg_new_stream(s, serial, 0);
+        } else {
+            idx = ogg_new_stream(s, serial, 1);
+        }
         if (idx < 0)
-            return -1;
+            return idx;
     }
 
     os = ogg->streams + idx;
+    os->page_pos = avio_tell(bc) - 27;
 
     if(os->psize > 0)
         ogg_new_buf(ogg, idx);
 
-    if (get_buffer (bc, os->segments, nsegs) < nsegs)
-        return -1;
+    ret = avio_read(bc, os->segments, nsegs);
+    if (ret < nsegs)
+        return ret < 0 ? ret : AVERROR_EOF;
 
     os->nsegs = nsegs;
     os->segp = 0;
@@ -265,17 +281,19 @@ ogg_read_page (AVFormatContext * s, int *str)
     for (i = 0; i < nsegs; i++)
         size += os->segments[i];
 
-    if (flags & OGG_FLAG_CONT){
+    if (flags & OGG_FLAG_CONT || os->incomplete){
         if (!os->psize){
             while (os->segp < os->nsegs){
                 int seg = os->segments[os->segp++];
                 os->pstart += seg;
                 if (seg < 255)
-                  break;
+                    break;
             }
+            os->sync_pos = os->page_pos;
         }
     }else{
-      os->psize = 0;
+        os->psize = 0;
+        os->sync_pos = os->page_pos;
     }
 
     if (os->bufsize - os->bufpos < size){
@@ -285,10 +303,10 @@ ogg_read_page (AVFormatContext * s, int *str)
         os->buf = nb;
     }
 
-    if (get_buffer (bc, os->buf + os->bufpos, size) < size)
-        return -1;
+    ret = avio_read(bc, os->buf + os->bufpos, size);
+    if (ret < size)
+        return ret < 0 ? ret : AVERROR_EOF;
 
-    os->lastgp = os->granule;
     os->bufpos += size;
     os->granule = gp;
     os->flags = flags;
@@ -299,39 +317,36 @@ ogg_read_page (AVFormatContext * s, int *str)
     return 0;
 }
 
-static int
-ogg_packet (AVFormatContext * s, int *str, int *dstart, int *dsize)
+static int ogg_packet(AVFormatContext *s, int *str, int *dstart, int *dsize,
+                      int64_t *fpos)
 {
-    ogg_t *ogg = s->priv_data;
-    int idx;
-    ogg_stream_t *os;
+    struct ogg *ogg = s->priv_data;
+    int idx, i, ret;
+    struct ogg_stream *os;
     int complete = 0;
     int segp = 0, psize = 0;
 
-#if 0
-    av_log (s, AV_LOG_DEBUG, "ogg_packet: curidx=%i\n", ogg->curidx);
-#endif
+    av_dlog(s, "ogg_packet: curidx=%i\n", ogg->curidx);
 
     do{
         idx = ogg->curidx;
 
         while (idx < 0){
-            if (ogg_read_page (s, &idx) < 0)
-                return -1;
+            ret = ogg_read_page(s, &idx);
+            if (ret < 0)
+                return ret;
         }
 
         os = ogg->streams + idx;
 
-#if 0
-        av_log (s, AV_LOG_DEBUG,
-                "ogg_packet: idx=%d pstart=%d psize=%d segp=%d nsegs=%d\n",
+        av_dlog(s, "ogg_packet: idx=%d pstart=%d psize=%d segp=%d nsegs=%d\n",
                 idx, os->pstart, os->psize, os->segp, os->nsegs);
-#endif
 
         if (!os->codec){
             if (os->header < 0){
                 os->codec = ogg_find_codec (os->buf, os->bufpos);
                 if (!os->codec){
+                    av_log(s, AV_LOG_WARNING, "Codec not found\n");
                     os->header = 0;
                     return 0;
                 }
@@ -354,32 +369,49 @@ ogg_packet (AVFormatContext * s, int *str, int *dstart, int *dsize)
 
         if (!complete && os->segp == os->nsegs){
             ogg->curidx = -1;
+            os->incomplete = 1;
         }
     }while (!complete);
 
-#if 0
-    av_log (s, AV_LOG_DEBUG,
-            "ogg_packet: idx %i, frame size %i, start %i\n",
+    av_dlog(s, "ogg_packet: idx %i, frame size %i, start %i\n",
             idx, os->psize, os->pstart);
-#endif
 
-    ogg->curidx = idx;
+    if (os->granule == -1)
+        av_log(s, AV_LOG_WARNING, "Page at %"PRId64" is missing granule\n", os->page_pos);
 
-    if (os->header < 0){
-        int hdr = os->codec->header (s, idx);
-        if (!hdr){
-          os->header = os->seq;
-          os->segp = segp;
-          os->psize = psize;
-          ogg->headers = 1;
+    ogg->curidx = idx;
+    os->incomplete = 0;
+
+    if (os->header) {
+        os->header = os->codec->header (s, idx);
+        if (!os->header){
+            os->segp = segp;
+            os->psize = psize;
+
+            // We have reached the first non-header packet in this stream.
+            // Unfortunately more header packets may still follow for others,
+            // but if we continue with header parsing we may lose data packets.
+            ogg->headers = 1;
+
+            // Update the header state for all streams and
+            // compute the data_offset.
+            if (!s->data_offset)
+                s->data_offset = os->sync_pos;
+            for (i = 0; i < ogg->nstreams; i++) {
+                struct ogg_stream *cur_os = ogg->streams + i;
+
+                // if we have a partial non-header packet, its start is
+                // obviously at or after the data start
+                if (cur_os->incomplete)
+                    s->data_offset = FFMIN(s->data_offset, cur_os->sync_pos);
+            }
         }else{
-          os->pstart += os->psize;
-          os->psize = 0;
+            os->pstart += os->psize;
+            os->psize = 0;
         }
-    }
-
-    if (os->header > -1 && os->seq > os->header){
+    } else {
         os->pflags = 0;
+        os->pduration = 0;
         if (os->codec && os->codec->packet)
             os->codec->packet (s, idx);
         if (str)
@@ -388,110 +420,93 @@ ogg_packet (AVFormatContext * s, int *str, int *dstart, int *dsize)
             *dstart = os->pstart;
         if (dsize)
             *dsize = os->psize;
+        if (fpos)
+            *fpos = os->sync_pos;
         os->pstart += os->psize;
         os->psize = 0;
+        os->sync_pos = os->page_pos;
     }
 
-    os->seq++;
+    // determine whether there are more complete packets in this page
+    // if not, the page's granule will apply to this packet
+    os->page_end = 1;
+    for (i = os->segp; i < os->nsegs; i++)
+        if (os->segments[i] < 255) {
+            os->page_end = 0;
+            break;
+        }
+
     if (os->segp == os->nsegs)
         ogg->curidx = -1;
 
     return 0;
 }
 
-static int
-ogg_get_headers (AVFormatContext * s)
+static int ogg_get_headers(AVFormatContext *s)
 {
-    ogg_t *ogg = s->priv_data;
+    struct ogg *ogg = s->priv_data;
+    int ret;
 
     do{
-        if (ogg_packet (s, NULL, NULL, NULL) < 0)
-            return -1;
+        ret = ogg_packet(s, NULL, NULL, NULL, NULL);
+        if (ret < 0)
+            return ret;
     }while (!ogg->headers);
 
-#if 0
-    av_log (s, AV_LOG_DEBUG, "found headers\n");
-#endif
+    av_dlog(s, "found headers\n");
 
     return 0;
 }
 
-static uint64_t
-ogg_gptopts (AVFormatContext * s, int i, uint64_t gp)
-{
-    ogg_t *ogg = s->priv_data;
-    ogg_stream_t *os = ogg->streams + i;
-    uint64_t pts = AV_NOPTS_VALUE;
-
-    if(os->codec->gptopts){
-        pts = os->codec->gptopts(s, i, gp);
-    } else {
-        pts = gp;
-    }
-
-    return pts;
-}
-
-
-static int
-ogg_get_length (AVFormatContext * s)
+static int ogg_get_length(AVFormatContext *s)
 {
-    ogg_t *ogg = s->priv_data;
-    int idx = -1, i;
-    offset_t size, end;
+    struct ogg *ogg = s->priv_data;
+    int i;
+    int64_t size, end;
 
-    if(url_is_streamed(s->pb))
+    if(!s->pb->seekable)
         return 0;
 
 // already set
     if (s->duration != AV_NOPTS_VALUE)
         return 0;
 
-    size = url_fsize(s->pb);
+    size = avio_size(s->pb);
     if(size < 0)
         return 0;
-    end = size > MAX_PAGE_SIZE? size - MAX_PAGE_SIZE: size;
+    end = size > MAX_PAGE_SIZE? size - MAX_PAGE_SIZE: 0;
 
     ogg_save (s);
-    url_fseek (s->pb, end, SEEK_SET);
+    avio_seek (s->pb, end, SEEK_SET);
 
     while (!ogg_read_page (s, &i)){
         if (ogg->streams[i].granule != -1 && ogg->streams[i].granule != 0 &&
-            ogg->streams[i].codec)
-            idx = i;
-    }
-
-    if (idx != -1){
-        s->streams[idx]->duration =
-            ogg_gptopts (s, idx, ogg->streams[idx].granule);
+            ogg->streams[i].codec) {
+            s->streams[i]->duration =
+                ogg_gptopts (s, i, ogg->streams[i].granule, NULL);
+            if (s->streams[i]->start_time != AV_NOPTS_VALUE)
+                s->streams[i]->duration -= s->streams[i]->start_time;
+        }
     }
 
-    ogg->size = size;
-    ogg_restore (s, 0);
-    ogg_save (s);
-    while (!ogg_read_page (s, &i)) {
-        if (i == idx && ogg->streams[i].granule != -1 && ogg->streams[i].granule != 0)
-            break;
-    }
-    if (i == idx) {
-        s->streams[idx]->start_time = ogg_gptopts (s, idx, ogg->streams[idx].granule);
-        s->streams[idx]->duration -= s->streams[idx]->start_time;
-    }
     ogg_restore (s, 0);
 
     return 0;
 }
 
-
-static int
-ogg_read_header (AVFormatContext * s, AVFormatParameters * ap)
+static int ogg_read_header(AVFormatContext *s)
 {
-    ogg_t *ogg = s->priv_data;
+    struct ogg *ogg = s->priv_data;
+    int ret, i;
     ogg->curidx = -1;
     //linear headers seek from start
-    if (ogg_get_headers (s) < 0){
-      return -1;
-    }
+    ret = ogg_get_headers(s);
+    if (ret < 0)
+        return ret;
+
+    for (i = 0; i < ogg->nstreams; i++)
+        if (ogg->streams[i].header < 0)
+            ogg->streams[i].codec = NULL;
 
     //linear granulepos seek from end
     ogg_get_length (s);
@@ -500,44 +515,81 @@ ogg_read_header (AVFormatContext * s, AVFormatParameters * ap)
     return 0;
 }
 
+static int64_t ogg_calc_pts(AVFormatContext *s, int idx, int64_t *dts)
+{
+    struct ogg *ogg = s->priv_data;
+    struct ogg_stream *os = ogg->streams + idx;
+    int64_t pts = AV_NOPTS_VALUE;
+
+    if (dts)
+        *dts = AV_NOPTS_VALUE;
+
+    if (os->lastpts != AV_NOPTS_VALUE) {
+        pts = os->lastpts;
+        os->lastpts = AV_NOPTS_VALUE;
+    }
+    if (os->lastdts != AV_NOPTS_VALUE) {
+        if (dts)
+            *dts = os->lastdts;
+        os->lastdts = AV_NOPTS_VALUE;
+    }
+    if (os->page_end) {
+        if (os->granule != -1LL) {
+            if (os->codec && os->codec->granule_is_start)
+                pts = ogg_gptopts(s, idx, os->granule, dts);
+            else
+                os->lastpts = ogg_gptopts(s, idx, os->granule, &os->lastdts);
+            os->granule = -1LL;
+        }
+    }
+    return pts;
+}
 
-static int
-ogg_read_packet (AVFormatContext * s, AVPacket * pkt)
+static int ogg_read_packet(AVFormatContext *s, AVPacket *pkt)
 {
-    ogg_t *ogg;
-    ogg_stream_t *os;
-    int idx = -1;
+    struct ogg *ogg;
+    struct ogg_stream *os;
+    int idx = -1, ret;
     int pstart, psize;
+    int64_t fpos, pts, dts;
 
     //Get an ogg packet
+retry:
     do{
-        if (ogg_packet (s, &idx, &pstart, &psize) < 0)
-            return AVERROR(EIO);
+        ret = ogg_packet(s, &idx, &pstart, &psize, &fpos);
+        if (ret < 0)
+            return ret;
     }while (idx < 0 || !s->streams[idx]);
 
     ogg = s->priv_data;
     os = ogg->streams + idx;
 
+    // pflags might not be set until after this
+    pts = ogg_calc_pts(s, idx, &dts);
+
+    if (os->keyframe_seek && !(os->pflags & AV_PKT_FLAG_KEY))
+        goto retry;
+    os->keyframe_seek = 0;
+
     //Alloc a pkt
-    if (av_new_packet (pkt, psize) < 0)
-        return AVERROR(EIO);
+    ret = av_new_packet(pkt, psize);
+    if (ret < 0)
+        return ret;
     pkt->stream_index = idx;
     memcpy (pkt->data, os->buf + pstart, psize);
-    if (os->lastgp != -1LL){
-        pkt->pts = ogg_gptopts (s, idx, os->lastgp);
-        os->lastgp = -1;
-    }
 
+    pkt->pts = pts;
+    pkt->dts = dts;
     pkt->flags = os->pflags;
+    pkt->duration = os->pduration;
+    pkt->pos = fpos;
 
     return psize;
 }
 
-
-static int
-ogg_read_close (AVFormatContext * s)
+static int ogg_read_close(AVFormatContext *s)
 {
-    ogg_t *ogg = s->priv_data;
+    struct ogg *ogg = s->priv_data;
     int i;
 
     for (i = 0; i < ogg->nstreams; i++){
@@ -548,49 +600,67 @@ ogg_read_close (AVFormatContext * s)
     return 0;
 }
 
-
-static int64_t
-ogg_read_timestamp (AVFormatContext * s, int stream_index, int64_t * pos_arg,
-                    int64_t pos_limit)
+static int64_t ogg_read_timestamp(AVFormatContext *s, int stream_index,
+                                  int64_t *pos_arg, int64_t pos_limit)
 {
-    ogg_t *ogg = s->priv_data;
-    ByteIOContext *bc = s->pb;
+    struct ogg *ogg = s->priv_data;
+    AVIOContext *bc = s->pb;
     int64_t pts = AV_NOPTS_VALUE;
-    int i;
-    url_fseek(bc, *pos_arg, SEEK_SET);
-    while (url_ftell(bc) < pos_limit && !ogg_read_page (s, &i)) {
-        if (ogg->streams[i].granule != -1 && ogg->streams[i].granule != 0 &&
-            ogg->streams[i].codec && i == stream_index) {
-            pts = ogg_gptopts(s, i, ogg->streams[i].granule);
-            // FIXME: this is the position of the packet after the one with above
-            // pts.
-            *pos_arg = url_ftell(bc);
-            break;
+    int i = -1;
+    avio_seek(bc, *pos_arg, SEEK_SET);
+    ogg_reset(ogg);
+
+    while (avio_tell(bc) < pos_limit && !ogg_packet(s, &i, NULL, NULL, pos_arg)) {
+        if (i == stream_index) {
+            struct ogg_stream *os = ogg->streams + stream_index;
+            pts = ogg_calc_pts(s, i, NULL);
+            if (os->keyframe_seek && !(os->pflags & AV_PKT_FLAG_KEY))
+                pts = AV_NOPTS_VALUE;
         }
+        if (pts != AV_NOPTS_VALUE)
+            break;
     }
     ogg_reset(ogg);
     return pts;
 }
 
+static int ogg_read_seek(AVFormatContext *s, int stream_index,
+                         int64_t timestamp, int flags)
+{
+    struct ogg *ogg = s->priv_data;
+    struct ogg_stream *os = ogg->streams + stream_index;
+    int ret;
+
+    // Try seeking to a keyframe first. If this fails (very possible),
+    // av_seek_frame will fall back to ignoring keyframes
+    if (s->streams[stream_index]->codec->codec_type == AVMEDIA_TYPE_VIDEO
+        && !(flags & AVSEEK_FLAG_ANY))
+        os->keyframe_seek = 1;
+
+    ret = ff_seek_frame_binary(s, stream_index, timestamp, flags);
+    os = ogg->streams + stream_index;
+    if (ret < 0)
+        os->keyframe_seek = 0;
+    return ret;
+}
+
 static int ogg_probe(AVProbeData *p)
 {
-    if (p->buf[0] == 'O' && p->buf[1] == 'g' &&
-        p->buf[2] == 'g' && p->buf[3] == 'S' &&
-        p->buf[4] == 0x0 && p->buf[5] <= 0x7 )
+    if (!memcmp("OggS", p->buf, 5) && p->buf[5] <= 0x7)
         return AVPROBE_SCORE_MAX;
-    else
-        return 0;
+    return 0;
 }
 
-AVInputFormat ogg_demuxer = {
-    "ogg",
-    NULL_IF_CONFIG_SMALL("Ogg"),
-    sizeof (ogg_t),
-    ogg_probe,
-    ogg_read_header,
-    ogg_read_packet,
-    ogg_read_close,
-    NULL,
-    ogg_read_timestamp,
-    .extensions = "ogg",
+AVInputFormat ff_ogg_demuxer = {
+    .name           = "ogg",
+    .long_name      = NULL_IF_CONFIG_SMALL("Ogg"),
+    .priv_data_size = sizeof(struct ogg),
+    .read_probe     = ogg_probe,
+    .read_header    = ogg_read_header,
+    .read_packet    = ogg_read_packet,
+    .read_close     = ogg_read_close,
+    .read_seek      = ogg_read_seek,
+    .read_timestamp = ogg_read_timestamp,
+    .extensions     = "ogg",
+    .flags          = AVFMT_GENERIC_INDEX,
 };