demux: include beginning of stream state in cached seekable range

Similar to 1eec7d2315, but for the beginning of the stream (named BOF in
this commit).

We can know this only if demuxing actually started from the beginning.
If there is a seek to the beginning (even if you use --start=-1000), we
don't know in general whether the demuxer truly returns the start of the
file. We could probably make a heuristic with assuming that this is what
happens if the seek target is before the start time or so, but this is
not included in this commit.

1 files changed, 19 insertions, 5 deletions

diff --git a/demux/demux.c b/demux/demux.c
index a748a3b5b0..9646bf4f64 100644
--- a/demux/demux.c
+++ b/demux/demux.c
@@ -217,8 +217,8 @@ struct demux_cached_range {
     // demux_queue) are always either NOPTS, or fully valid.
     double seek_start, seek_end;
 
-    // Set if the file ends with this range.
-    bool is_eof;
+    bool is_bof;            // set if the file begins with this range
+    bool is_eof;            // set if the file ends with this range
 };
 
 #define MAX_INDEX_ENTRIES 16
@@ -249,6 +249,7 @@ struct demux_queue {
     double seek_start, seek_end;
     double last_pruned;     // timestamp of last pruned keyframe
 
+    bool is_bof;            // started demuxing at beginning of file
     bool is_eof;            // received true EOF here
 
     // incomplete index to somewhat speed up seek operations
@@ -428,6 +429,7 @@ static void set_current_range(struct demux_internal *in,
 static void update_seek_ranges(struct demux_cached_range *range)
 {
     range->seek_start = range->seek_end = MP_NOPTS_VALUE;
+    range->is_bof = true;
     range->is_eof = true;
 
     for (int n = 0; n < range->num_streams; n++) {
@@ -438,6 +440,7 @@ static void update_seek_ranges(struct demux_cached_range *range)
             range->seek_end = MP_PTS_MIN(range->seek_end, queue->seek_end);
 
             range->is_eof &= queue->is_eof;
+            range->is_bof &= queue->is_bof;
 
             if (queue->seek_start >= queue->seek_end) {
                 range->seek_start = range->seek_end = MP_NOPTS_VALUE;
@@ -486,6 +489,7 @@ static void remove_head_packet(struct demux_queue *queue)
         queue->next_prune_target = NULL;
     if (queue->keyframe_latest == dp)
         queue->keyframe_latest = NULL;
+    queue->is_bof = false;
 
     queue->ds->in->total_bytes -= demux_packet_estimate_total_size(dp);
 
@@ -527,6 +531,7 @@ static void clear_queue(struct demux_queue *queue)
     queue->keyframe_pts = queue->keyframe_end_pts = MP_NOPTS_VALUE;
 
     queue->is_eof = false;
+    queue->is_bof = false;
 }
 
 static void clear_cached_range(struct demux_internal *in,
@@ -1155,6 +1160,8 @@ void demux_add_packet(struct sh_stream *stream, demux_packet_t *dp)
     struct demux_internal *in = ds->in;
     pthread_mutex_lock(&in->lock);
 
+    in->initial_state = false;
+
     double ts = dp->dts == MP_NOPTS_VALUE ? dp->pts : dp->dts;
     if (dp->segmented)
         ts = MP_PTS_MIN(ts, dp->end);
@@ -1324,6 +1331,11 @@ static bool read_packet(struct demux_internal *in)
     if (!read_more && !prefetch_more && !refresh_more)
         return false;
 
+    if (in->initial_state) {
+        for (int n = 0; n < in->num_streams; n++)
+            in->current_range->streams[n]->is_bof = in->streams[n]->ds->selected;
+    }
+
     // Actually read a packet. Drop the lock while doing so, because waiting
     // for disk or network I/O can take time.
     in->idle = false;
@@ -2325,10 +2337,12 @@ static struct demux_cached_range *find_cache_seek_target(struct demux_internal *
     for (int n = 0; n < in->num_ranges; n++) {
         struct demux_cached_range *r = in->ranges[n];
         if (r->seek_start != MP_NOPTS_VALUE) {
-            MP_VERBOSE(in, "cached range %d: %f <-> %f (eof=%d)\n",
-                       n, r->seek_start, r->seek_end, r->is_eof);
+            MP_VERBOSE(in, "cached range %d: %f <-> %f (bof=%d, eof=%d)\n",
+                       n, r->seek_start, r->seek_end, r->is_bof, r->is_eof);
 
-            if (pts >= r->seek_start && (pts <= r->seek_end || r->is_eof)) {
+            if ((pts >= r->seek_start || r->is_bof) &&
+                (pts <= r->seek_end || r->is_eof))
+            {
                 MP_VERBOSE(in, "...using this range for in-cache seek.\n");
                 return r;
             }