[FFmpeg-devel] [PATCH 2/3] avformat/fifo: add option to write packets in paced way

[leozhang]

Signed-off-by: leozhang <leozhang at qiyi.com>
---
 doc/muxers.texi    |  3 +++
 libavformat/fifo.c | 19 +++++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/doc/muxers.texi b/doc/muxers.texi
index a74cbc4..5140c00 100644
--- a/doc/muxers.texi
+++ b/doc/muxers.texi
@@ -2274,6 +2274,9 @@ queue overflow or failure. This option is set to 0 (false) by default.
 @item output_delay
 Time to delay output, in microseconds. Default value is 0.
 
+ at item paced
+If set to 1 (true), write packets in paced way. Default value is 0 (false).
+
 @end table
 
 @subsection Examples
diff --git a/libavformat/fifo.c b/libavformat/fifo.c
index bdecf2d..81b7e9e 100644
--- a/libavformat/fifo.c
+++ b/libavformat/fifo.c
@@ -79,6 +79,12 @@ typedef struct FifoContext {
 
     /* Time to delay output, in microseconds */
     uint64_t output_delay;
+
+    /* If set to 1, write packets in paced way */
+    int paced;
+
+    /* Time to start */
+    uint64_t start_time;
 } FifoContext;
 
 typedef struct FifoThreadContext {
@@ -184,6 +190,14 @@ static int fifo_thread_write_packet(FifoThreadContext *ctx, AVPacket *pkt)
     src_tb = avf->streams[s_idx]->time_base;
     dst_tb = avf2->streams[s_idx]->time_base;
     av_packet_rescale_ts(pkt, src_tb, dst_tb);
+    if (fifo->paced) {
+        uint64_t pts = av_rescale_q(pkt->dts, dst_tb, AV_TIME_BASE_Q);
+        uint64_t now = av_gettime_relative() - fifo->start_time;
+        av_assert0(now >= fifo->output_delay);
+        if (pts > now - fifo->output_delay) {
+            av_usleep(pts - (now - fifo->output_delay));
+        }
+    }
 
     ret = av_write_frame(avf2, pkt);
     if (ret >= 0)
@@ -515,6 +529,8 @@ static int fifo_init(AVFormatContext *avf)
         return AVERROR(ret);
     fifo->overflow_flag_lock_initialized = 1;
 
+    fifo->start_time = av_gettime_relative();
+
     return 0;
 }
 
@@ -637,6 +653,9 @@ static const AVOption options[] = {
         {"output_delay", "Time to delay output, in microseconds", OFFSET(output_delay),
          AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM},
 
+        {"paced", "Write packets in paced way", OFFSET(paced),
+         AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, AV_OPT_FLAG_ENCODING_PARAM},
+
         {NULL},
 };
 
-- 
1.8.3.1