From 45dd5c69f91eca28e03cffedfe10c4b5557a5ee7 Mon Sep 17 00:00:00 2001
From: Fabrice Bellard <fabrice@bellard.org>
Date: Tue, 19 Nov 2002 15:52:29 +0000
Subject: [PATCH] a/v sync support: added correct pts handling

Originally committed as revision 1229 to svn://svn.ffmpeg.org/ffmpeg/trunk
---
 libav/audio.c | 35 ++++++++++++++++++++++++++---------
 libav/grab.c  |  7 +++++--
 2 files changed, 31 insertions(+), 11 deletions(-)

diff --git a/libav/audio.c b/libav/audio.c
index 06aad4e8e2..34da590916 100644
--- a/libav/audio.c
+++ b/libav/audio.c
@@ -220,21 +220,25 @@ static int audio_read_header(AVFormatContext *s1, AVFormatParameters *ap)
     if (ret < 0) {
         av_free(st);
         return -EIO;
-    } else {
-        /* take real parameters */
-        st->codec.codec_type = CODEC_TYPE_AUDIO;
-        st->codec.codec_id = s->codec_id;
-        st->codec.sample_rate = s->sample_rate;
-        st->codec.channels = s->channels;
-        return 0;
     }
+
+    /* take real parameters */
+    st->codec.codec_type = CODEC_TYPE_AUDIO;
+    st->codec.codec_id = s->codec_id;
+    st->codec.sample_rate = s->sample_rate;
+    st->codec.channels = s->channels;
+
+    av_set_pts_info(s1, 48, 1, 1000000);  /* 48 bits pts in us */
+    return 0;
 }
 
 static int audio_read_packet(AVFormatContext *s1, AVPacket *pkt)
 {
     AudioData *s = s1->priv_data;
-    int ret;
-
+    int ret, bdelay;
+    int64_t cur_time;
+    struct audio_buf_info abufi;
+    
     if (av_new_packet(pkt, s->frame_size) < 0)
         return -EIO;
     for(;;) {
@@ -252,6 +256,19 @@ static int audio_read_packet(AVFormatContext *s1, AVPacket *pkt)
         }
     }
     pkt->size = ret;
+
+    /* compute pts of the start of the packet */
+    cur_time = av_gettime();
+    bdelay = ret;
+    if (ioctl(s->fd, SNDCTL_DSP_GETISPACE, &abufi) == 0) {
+        bdelay += abufi.bytes;
+    }
+    /* substract time represented by the number of bytes in the audio fifo */
+    cur_time -= (bdelay * 1000000LL) / (s->sample_rate * s->channels);
+
+    /* convert to wanted units */
+    pkt->pts = cur_time & ((1LL << 48) - 1);
+
     if (s->flip_left && s->channels == 2) {
         int i;
         short *p = (short *) pkt->data;
diff --git a/libav/grab.c b/libav/grab.c
index 3d7c08a4a9..9bb9e93be9 100644
--- a/libav/grab.c
+++ b/libav/grab.c
@@ -240,6 +240,8 @@ static int grab_read_header(AVFormatContext *s1, AVFormatParameters *ap)
     st->codec.height = height;
     st->codec.frame_rate = frame_rate;
 
+    av_set_pts_info(s1, 48, 1, 1000000); /* 48 bits pts in us */
+
     return 0;
  fail:
     if (video_fd >= 0)
@@ -279,7 +281,6 @@ static int grab_read_packet(AVFormatContext *s1, AVPacket *pkt)
     VideoData *s = s1->priv_data;
     INT64 curtime, delay;
     struct timespec ts;
-    int first;
     INT64 per_frame = (INT64_C(1000000) * FRAME_RATE_BASE) / s->frame_rate;
     int dropped = 0;
 
@@ -287,7 +288,7 @@ static int grab_read_packet(AVFormatContext *s1, AVPacket *pkt)
     s->time_frame += per_frame;
 
     /* wait based on the frame rate */
-    for(first = 1;; first = 0) {
+    for(;;) {
         curtime = av_gettime();
         delay = s->time_frame - curtime;
         if (delay <= 0) {
@@ -306,6 +307,8 @@ static int grab_read_packet(AVFormatContext *s1, AVPacket *pkt)
     if (av_new_packet(pkt, s->frame_size) < 0)
         return -EIO;
 
+    pkt->pts = curtime & ((1LL << 48) - 1);
+
     if (dropped)
         pkt->flags |= PKT_FLAG_DROPPED_FRAME;