command: add properties for current bitrate

Fixes #1192.

4 files changed, 67 insertions, 1 deletions

diff --git a/DOCS/man/input.rst b/DOCS/man/input.rst
index fc0640553b..dd2c20bee3 100644
--- a/DOCS/man/input.rst
+++ b/DOCS/man/input.rst
@@ -1445,6 +1445,17 @@ Property list
     whether the video window is visible. If the ``--force-window`` option is
     used, this is usually always returns ``yes``.
 
+``packet-video-bitrate``, ``packet-audio-bitrate``, ``packet-sub-bitrate``
+    Bitrate values calculated on the packet level. This works by dividing the
+    bit size of all packets between two keyframes by their presentation
+    timestamp distance. (This uses the timestamps are stored in the file, so
+    e.g. playback speed does not influence the returned values.) In particular,
+    the video bitrate will update only per keyframe, and show the "past"
+    bitrate. To make the property more UI friendly, updates to these properties
+    are throttled in a certain way.
+
+    How exactly these values are calculated might change in the future.
+
 ``audio-device-list``
     Return the list of discovered audio devices. This is mostly for use with
     the client API, and reflects what ``--audio-device=help`` with the command
diff --git a/demux/demux.c b/demux/demux.c
index ea0464cdae..e7b0729b77 100644
--- a/demux/demux.c
+++ b/demux/demux.c
@@ -146,6 +146,9 @@ struct demux_stream {
     size_t bytes;           // total bytes of packets in buffer
     double base_ts;         // timestamp of the last packet returned to decoder
     double last_ts;         // timestamp of the last packet added to queue
+    double last_br_ts;      // timestamp of last packet bitrate was calculated
+    size_t last_br_bytes;   // summed packet sizes since last bitrate calculation
+    double bitrate;
     struct demux_packet *head;
     struct demux_packet *tail;
 };
@@ -172,7 +175,9 @@ static void ds_flush(struct demux_stream *ds)
     ds->head = ds->tail = NULL;
     ds->packs = 0;
     ds->bytes = 0;
-    ds->last_ts = ds->base_ts = MP_NOPTS_VALUE;
+    ds->last_ts = ds->base_ts = ds->last_br_ts = MP_NOPTS_VALUE;
+    ds->last_br_bytes = 0;
+    ds->bitrate = -1;
     ds->eof = false;
     ds->active = false;
 }
@@ -514,6 +519,22 @@ static struct demux_packet *dequeue_packet(struct demux_stream *ds)
     if (ts != MP_NOPTS_VALUE)
         ds->base_ts = ts;
 
+    if (pkt->keyframe) {
+        // Update bitrate - only at keyframe points, because we use the
+        // (possibly) reordered packet timestamps instead of realtime.
+        double d = ts - ds->last_br_ts;
+        if (ts == MP_NOPTS_VALUE || ds->last_br_ts == MP_NOPTS_VALUE || d < 0) {
+            ds->bitrate = -1;
+            ds->last_br_ts = ts;
+            ds->last_br_bytes = 0;
+        } else if (d > 0 && d >= 0.5) { // a window of least 500ms for UI purposes
+            ds->bitrate = ds->last_br_bytes / d;
+            ds->last_br_ts = ts;
+            ds->last_br_bytes = 0;
+        }
+    }
+    ds->last_br_bytes += pkt->len;
+
     // This implies this function is actually called from "the" user thread.
     if (pkt->pos >= ds->in->d_user->filepos)
         ds->in->d_user->filepos = pkt->pos;
@@ -1233,6 +1254,16 @@ static int cached_demux_control(struct demux_internal *in, int cmd, void *arg)
         in->tracks_switched = true;
         pthread_cond_signal(&in->wakeup);
         return DEMUXER_CTRL_OK;
+    case DEMUXER_CTRL_GET_BITRATE_STATS: {
+        double *rates = arg;
+        for (int n = 0; n < STREAM_TYPE_COUNT; n++)
+            rates[n] = 0;
+        for (int n = 0; n < in->d_user->num_streams; n++) {
+            struct demux_stream *ds = in->d_user->streams[n]->ds;
+            rates[ds->type] += MPMAX(0, ds->bitrate);
+        }
+        return DEMUXER_CTRL_OK;
+    }
     case DEMUXER_CTRL_GET_READER_STATE: {
         struct demux_ctrl_reader_state *r = arg;
         *r = (struct demux_ctrl_reader_state){
diff --git a/demux/demux.h b/demux/demux.h
index 39bfee7fea..ca96d60732 100644
--- a/demux/demux.h
+++ b/demux/demux.h
@@ -56,6 +56,7 @@ enum demux_ctrl {
     DEMUXER_CTRL_STREAM_CTRL,
     DEMUXER_CTRL_GET_READER_STATE,
     DEMUXER_CTRL_GET_NAV_EVENT,
+    DEMUXER_CTRL_GET_BITRATE_STATS, // double[STREAM_TYPE_COUNT]
 };
 
 struct demux_ctrl_reader_state {
diff --git a/player/command.c b/player/command.c
index 2387eb25d8..1b7156bb6c 100644
--- a/player/command.c
+++ b/player/command.c
@@ -2970,6 +2970,23 @@ static int mp_property_ab_loop(void *ctx, struct m_property *prop,
     return r;
 }
 
+static int mp_property_packet_bitrate(void *ctx, struct m_property *prop,
+                                      int action, void *arg)
+{
+    MPContext *mpctx = ctx;
+    int type = (intptr_t)prop->priv;
+
+    if (!mpctx->demuxer)
+        return M_PROPERTY_UNAVAILABLE;
+
+    double r[STREAM_TYPE_COUNT];
+    if (demux_control(mpctx->demuxer, DEMUXER_CTRL_GET_BITRATE_STATS, &r) < 1)
+        return M_PROPERTY_UNAVAILABLE;
+
+    // r[type] is in bytes/second -> kilobits
+    return m_property_int64_ro(action, arg, r[type] * 8 / 1000.0 + 0.5);
+}
+
 static int mp_property_version(void *ctx, struct m_property *prop,
                                int action, void *arg)
 {
@@ -3301,6 +3318,12 @@ static const struct m_property mp_properties[] = {
     {"ab-loop-a", mp_property_ab_loop},
     {"ab-loop-b", mp_property_ab_loop},
 
+#define PROPERTY_BITRATE(name, type) \
+    {name, mp_property_packet_bitrate, (void *)(intptr_t)type}
+    PROPERTY_BITRATE("packet-video-bitrate", STREAM_VIDEO),
+    PROPERTY_BITRATE("packet-audio-bitrate", STREAM_AUDIO),
+    PROPERTY_BITRATE("packet-sub-bitrate", STREAM_SUB),
+
 #define PROPERTY_TV_COLOR(name, type) \
     {name, mp_property_tv_color, (void *)(intptr_t)type}
     PROPERTY_TV_COLOR("tv-brightness", TV_COLOR_BRIGHTNESS),