demux: remove relative seeking

Ever since a change in mplayer2 or so, relative seeks were translated to
absolute seeks before sending them to the demuxer in most cases. The
only exception in current mpv is DVD seeking.

Remove the SEEK_ABSOLUTE flag; it's not the implied default. SEEK_FACTOR
is kept, because it's sometimes slightly useful for seeking in things
like transport streams. (And maybe mkv files without duration set?)

DVD seeking is terrible because DVD and libdvdnav are terrible, but
mostly because libdvdnav is terrible. libdvdnav does not expose seeking
with seek tables. (Although I know xbmc/kodi use an undocumented API
that is not declared in the headers by dladdr()ing it - I think the
function is dvdnav_jump_to_sector_by_time().) With the current mpv
policy if not giving a shit about DVD, just revert our half-working seek
hacks and always use dvdnav_time_search(). Relative seeking might get
stuck sometimes; in this case --hr-seek=always is recommended.

1 files changed, 11 insertions, 23 deletions

diff --git a/demux/demux_lavf.c b/demux/demux_lavf.c
index 518dd0f8dd..8a92a2886f 100644
--- a/demux/demux_lavf.c
+++ b/demux/demux_lavf.c
@@ -164,7 +164,6 @@ typedef struct lavf_priv {
     int avif_flags;
     AVFormatContext *avfc;
     AVIOContext *pb;
-    int64_t last_pts;
     struct sh_stream **streams; // NULL for unknown streams
     int num_streams;
     int cur_program;
@@ -920,11 +919,6 @@ static int demux_lavf_fill_buffer(demuxer_t *demux)
 #endif
     dp->pos = pkt->pos;
     dp->keyframe = pkt->flags & AV_PKT_FLAG_KEY;
-    if (dp->pts != MP_NOPTS_VALUE) {
-        priv->last_pts = dp->pts * AV_TIME_BASE;
-    } else if (dp->dts != MP_NOPTS_VALUE) {
-        priv->last_pts = dp->dts * AV_TIME_BASE;
-    }
     av_packet_unref(pkt);
 
     if (priv->format_hack.clear_filepos)
@@ -934,19 +928,13 @@ static int demux_lavf_fill_buffer(demuxer_t *demux)
     return 1;
 }
 
-static void demux_seek_lavf(demuxer_t *demuxer, double rel_seek_secs, int flags)
+static void demux_seek_lavf(demuxer_t *demuxer, double seek_pts, int flags)
 {
     lavf_priv_t *priv = demuxer->priv;
     int avsflags = 0;
+    int64_t seek_pts_av = 0;
 
-    if (flags & SEEK_ABSOLUTE)
-        priv->last_pts = 0;
-    else if (rel_seek_secs < 0)
-        avsflags = AVSEEK_FLAG_BACKWARD;
-
-    if (flags & SEEK_FORWARD)
-        avsflags = 0;
-    else if (flags & SEEK_BACKWARD)
+    if (flags & SEEK_BACKWARD)
         avsflags = AVSEEK_FLAG_BACKWARD;
 
     if (flags & SEEK_FACTOR) {
@@ -956,28 +944,28 @@ static void demux_seek_lavf(demuxer_t *demuxer, double rel_seek_secs, int flags)
             !(priv->avif_flags & AVFMT_NO_BYTE_SEEK))
         {
             avsflags |= AVSEEK_FLAG_BYTE;
-            priv->last_pts = end * rel_seek_secs;
+            seek_pts_av = end * seek_pts;
         } else if (priv->avfc->duration != 0 &&
                    priv->avfc->duration != AV_NOPTS_VALUE)
         {
-            priv->last_pts = rel_seek_secs * priv->avfc->duration;
+            seek_pts_av = seek_pts * priv->avfc->duration;
         }
     } else {
         if (flags & SEEK_BACKWARD)
-            rel_seek_secs -= priv->seek_delay;
-        priv->last_pts += rel_seek_secs * AV_TIME_BASE;
+            seek_pts -= priv->seek_delay;
+        seek_pts_av = seek_pts * AV_TIME_BASE;
     }
 
     int r;
     if (!priv->avfc->iformat->read_seek2) {
         // Normal seeking.
-        r = av_seek_frame(priv->avfc, -1, priv->last_pts, avsflags);
+        r = av_seek_frame(priv->avfc, -1, seek_pts_av, avsflags);
         if (r < 0 && (avsflags & AVSEEK_FLAG_BACKWARD)) {
             // When seeking before the beginning of the file, and seeking fails,
             // try again without the backwards flag to make it seek to the
             // beginning.
             avsflags &= ~AVSEEK_FLAG_BACKWARD;
-            r = av_seek_frame(priv->avfc, -1, priv->last_pts, avsflags);
+            r = av_seek_frame(priv->avfc, -1, seek_pts_av, avsflags);
         }
     } else {
         // av_seek_frame() won't work. Use "new" seeking API. We don't use this
@@ -985,11 +973,11 @@ static void demux_seek_lavf(demuxer_t *demuxer, double rel_seek_secs, int flags)
         // Set max_ts==ts, so that demuxing starts from an earlier position in
         // the worst case.
         r = avformat_seek_file(priv->avfc, -1, INT64_MIN,
-                               priv->last_pts, priv->last_pts, avsflags);
+                               seek_pts_av, seek_pts_av, avsflags);
         // Similar issue as in the normal seeking codepath.
         if (r < 0) {
             r = avformat_seek_file(priv->avfc, -1, INT64_MIN,
-                                   priv->last_pts, INT64_MAX, avsflags);
+                                   seek_pts_av, INT64_MAX, avsflags);
         }
     }
     if (r < 0) {