[FFmpeg-devel] [PATCH 1/1] libavdevice/decklink: configurablity to set max queue size

[Patagar, Ravindra]

Configurablity to set max queue size so that worst case latency can be controlled.
Signed-off-by: Ravindra Patagar <rpatagar at akamai.com>
---
libavdevice/decklink_common.h   | 2 ++
libavdevice/decklink_common_c.h | 2 ++
libavdevice/decklink_dec.cpp    | 7 +++++--
libavdevice/decklink_dec_c.c    | 2 ++
4 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/libavdevice/decklink_common.h b/libavdevice/decklink_common.h
index c12cf18..64cc722 100644
--- a/libavdevice/decklink_common.h
+++ b/libavdevice/decklink_common.h
@@ -1,6 +1,7 @@
/*
  * Blackmagic DeckLink common code
  * Copyright (c) 2013-2014 Ramiro Polla, Luca Barbato, Deti Fliegl
+ * Copyright (c) 2017 Akamai Technologies, Inc.
  *
  * This file is part of FFmpeg.
  *
@@ -38,6 +39,7 @@ typedef struct AVPacketQueue {
     pthread_mutex_t mutex;
     pthread_cond_t cond;
     AVFormatContext *avctx;
+    int max_q_size;
} AVPacketQueue;

struct decklink_ctx {
diff --git a/libavdevice/decklink_common_c.h b/libavdevice/decklink_common_c.h
index 72c5f9a..0ddd32a 100644
--- a/libavdevice/decklink_common_c.h
+++ b/libavdevice/decklink_common_c.h
@@ -1,6 +1,7 @@
/*
  * Blackmagic DeckLink common code
  * Copyright (c) 2013-2014 Ramiro Polla
+ * Copyright (c) 2017 Akamai Technologies, Inc.
  *
  * This file is part of FFmpeg.
  *
@@ -48,6 +49,7 @@ struct decklink_cctx {
     int video_input;
     int draw_bars;
     char *format_code;
+    int queue_size;
};

#endif /* AVDEVICE_DECKLINK_COMMON_C_H */
diff --git a/libavdevice/decklink_dec.cpp b/libavdevice/decklink_dec.cpp
index 72449a8..8e85c65 100644
--- a/libavdevice/decklink_dec.cpp
+++ b/libavdevice/decklink_dec.cpp
@@ -1,6 +1,7 @@
/*
  * Blackmagic DeckLink input
  * Copyright (c) 2013-2014 Luca Barbato, Deti Fliegl
+ * Copyright (c) 2017 Akamai Technologies, Inc.
  *
  * This file is part of FFmpeg.
  *
@@ -187,10 +188,12 @@ static uint8_t* teletext_data_unit_from_vanc_data(uint8_t *src, uint8_t *tgt, in

static void avpacket_queue_init(AVFormatContext *avctx, AVPacketQueue *q)
{
+    struct decklink_cctx * ctx = (struct decklink_cctx *)avctx->priv_data;
     memset(q, 0, sizeof(AVPacketQueue));
     pthread_mutex_init(&q->mutex, NULL);
     pthread_cond_init(&q->cond, NULL);
     q->avctx = avctx;
+    q->max_q_size = ctx->queue_size;
}

static void avpacket_queue_flush(AVPacketQueue *q)
@@ -230,8 +233,8 @@ static int avpacket_queue_put(AVPacketQueue *q, AVPacket *pkt)
{
     AVPacketList *pkt1;

-    // Drop Packet if queue size is > 1GB
-    if (avpacket_queue_size(q) >  1024 * 1024 * 1024 ) {
+    // Drop Packet if queue size is > maximum queue size
+    if (avpacket_queue_size(q) >  q->max_q_size ) {
         av_log(q->avctx, AV_LOG_WARNING,  "Decklink input buffer overrun!\n");
         return -1;
     }
diff --git a/libavdevice/decklink_dec_c.c b/libavdevice/decklink_dec_c.c
index 5b26d12..ea828be 100644
--- a/libavdevice/decklink_dec_c.c
+++ b/libavdevice/decklink_dec_c.c
@@ -1,6 +1,7 @@
/*
  * Blackmagic DeckLink input
  * Copyright (c) 2014 Deti Fliegl
+ * Copyright (c) 2017 Akamai Technologies, Inc.
  *
  * This file is part of FFmpeg.
  *
@@ -64,6 +65,7 @@ static const AVOption options[] = {
     { "reference",     NULL,                                          0,  AV_OPT_TYPE_CONST, { .i64 = PTS_SRC_REFERENCE}, 0, 0, DEC, "pts_source"},
     { "wallclock",     NULL,                                          0,  AV_OPT_TYPE_CONST, { .i64 = PTS_SRC_WALLCLOCK}, 0, 0, DEC, "pts_source"},
     { "draw_bars",     "draw bars on signal loss" , OFFSET(draw_bars),    AV_OPT_TYPE_BOOL,  { .i64 = 1}, 0, 1, DEC },
+    { "qbufsize",      "Input queue buffer size",   OFFSET(queue_size),    AV_OPT_TYPE_INT,   { .i64 = (1024 * 1024 * 1024)}, 0, INT_MAX, DEC, "bytes"},
     { NULL },
};

--
1.9.1