From ef784dee016c6e47eb58bb8697f19fa1157b5e25 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cl=C3=A9ment=20B=C5=93sch?= <clement@stupeflix.com>
Date: Mon, 1 Dec 2014 17:25:09 +0100
Subject: [PATCH] avformat/RFC/WIP: add basic timeline support

---
 ffmpeg.c             |  3 +++
 ffplay.c             |  3 +++
 libavcodec/avcodec.h |  1 +
 libavformat/mov.c    | 66 +++++++++++++++++++++++++++++++++++++++++++++++++---
 4 files changed, 70 insertions(+), 3 deletions(-)

diff --git a/ffmpeg.c b/ffmpeg.c
index eef774b..a3ec228 100644
--- a/ffmpeg.c
+++ b/ffmpeg.c
@@ -2206,6 +2206,9 @@ static int process_input_packet(InputStream *ist, const AVPacket *pkt)
         if (ret < 0)
             return ret;
 
+        if (got_output && ist->decoded_frame && (avpkt.flags & AV_PKT_FLAG_NOPRESENTATION))
+            got_output = 0;
+
         avpkt.dts=
         avpkt.pts= AV_NOPTS_VALUE;
 
diff --git a/ffplay.c b/ffplay.c
index 1914a66..c28a004 100644
--- a/ffplay.c
+++ b/ffplay.c
@@ -610,6 +610,9 @@ static int decoder_decode_frame(Decoder *d, AVFrame *frame, AVSubtitle *sub) {
                 break;
         }
 
+        if (got_frame && frame && (d->pkt_temp.flags & AV_PKT_FLAG_NOPRESENTATION))
+            got_frame = 0;
+
         if (ret < 0) {
             d->packet_pending = 0;
         } else {
diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index dabae1b..b723deb 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -1195,6 +1195,7 @@ typedef struct AVPacket {
 } AVPacket;
 #define AV_PKT_FLAG_KEY     0x0001 ///< The packet contains a keyframe
 #define AV_PKT_FLAG_CORRUPT 0x0002 ///< The packet content is corrupted
+#define AV_PKT_FLAG_NOPRESENTATION 0x0010 ///< The packet should be decoded but ignored for presentation
 
 enum AVSideDataParamChangeFlags {
     AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_COUNT  = 0x0001,
diff --git a/libavformat/mov.c b/libavformat/mov.c
index 33c491a..27954fb 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -2241,8 +2241,7 @@ static void mov_build_index(MOVContext *mov, AVStream *st)
     unsigned int stps_index = 0;
     unsigned int i, j;
     uint64_t stream_size = 0;
-
-    if (sc->elst_count) {
+    if (0 && sc->elst_count) {
         int i, edit_start_index = 0, unsupported = 0;
         int64_t empty_duration = 0; // empty duration of the first edit list entry
         int64_t start_time = 0; // start time of the media
@@ -2622,7 +2621,6 @@ static int mov_read_trak(MOVContext *c, AVIOContext *pb, MOVAtom atom)
     av_freep(&sc->keyframes);
     av_freep(&sc->stts_data);
     av_freep(&sc->stps_data);
-    av_freep(&sc->elst_data);
     av_freep(&sc->rap_group);
 
     return 0;
@@ -4057,6 +4055,67 @@ static AVIndexEntry *mov_find_next_sample(AVFormatContext *s, AVStream **st)
     return sample;
 }
 
+static void packet_honor_timeline(const MOVElst *elst, int elst_count, AVPacket *pkt)
+{
+    int i;
+    int64_t total_drop_time = 0;
+
+    //av_log(0,0,"honor timeline elst=%p elst_count=%d pts=%"PRId64"\n", elst, elst_count, pkt->pts);
+
+    if (!elst || !elst_count || pkt->pts == AV_NOPTS_VALUE)
+        return;
+
+    /* If the first segment is an empty entry, the duration is the start time
+     * of the stream relative to the presentation itself */
+    if (elst[0].time == -1) {
+        const int64_t empty_initial_duration = elst[0].duration;
+        pkt->pts += empty_initial_duration;
+        //if (pkt->dts != AV_NOPTS_VALUE)
+        //    pkt->dts += empty_initial_duration;
+
+        av_log(0,0,"initial empty duration: %"PRId64"\n", empty_initial_duration);
+
+        /* If there is only this special entry, we can consider that the rest
+         * should be displayed */
+        if (elst_count == 1)
+            return;
+    }
+
+    for (i = 0; i < elst_count; i++) {
+        int64_t gap;
+        const MOVElst *segment = &elst[i];
+        const MOVElst *next    = i < elst_count - 1 ? &elst[i + 1] : NULL;
+        const MOVElst *prev    = i > 0              ? &elst[i - 1] : NULL;
+        int64_t end = segment->duration ? segment->time + segment->duration : -1;
+
+        if (!segment->duration && next)
+            end = next->time;
+
+        if (prev) gap = segment->time - prev->time - prev->duration;
+        else      gap = segment->time;
+
+        total_drop_time += gap * segment->rate;
+
+        if (pkt->pts >= segment->time && (end == -1 || pkt->pts <= end))
+            break;
+    }
+
+    if (i == elst_count) {
+        pkt->flags |= AV_PKT_FLAG_NOPRESENTATION;
+        av_log(0,0,"pts=%"PRId64" -> not part of the presentation\n", pkt->pts);
+    } else {
+        if (total_drop_time)
+            av_log(0,0,"[%"PRId64"] pts:%"PRId64"->%"PRId64" dts:%"PRId64"->%"PRId64"\n",
+                   -total_drop_time,
+                   pkt->pts, pkt->pts - total_drop_time,
+                   pkt->dts, pkt->dts - total_drop_time);
+        pkt->pts -= total_drop_time;
+        //if (pkt->dts != AV_NOPTS_VALUE)
+        //    pkt->dts -= total_drop_time;
+        // TODO: if audio, add a side data to truncate
+    }
+}
+
 static int mov_read_packet(AVFormatContext *s, AVPacket *pkt)
 {
     MOVContext *mov = s->priv_data;
@@ -4143,6 +4202,7 @@ static int mov_read_packet(AVFormatContext *s, AVPacket *pkt)
         goto retry;
     pkt->flags |= sample->flags & AVINDEX_KEYFRAME ? AV_PKT_FLAG_KEY : 0;
     pkt->pos = sample->pos;
+    packet_honor_timeline(sc->elst_data, sc->elst_count, pkt);
     av_dlog(s, "stream %d, pts %"PRId64", dts %"PRId64", pos 0x%"PRIx64", duration %d\n",
             pkt->stream_index, pkt->pts, pkt->dts, pkt->pos, pkt->duration);
     return 0;
-- 
2.1.3