[FFmpeg-devel] [PATCH v4 2/9] lavc/libopenh264enc: add default gop size and bit rate

[Linjie Fu]

It would be 200kbps bitrate with gop size = 12 by default
which generated too many IDR frames in rather low bit rate.
The quality would be poor.

Set these default values according to vaapi encoder, and
use 2Mbps bitrate if user doesn't set it explicitly as
nvenc sugguested.

Signed-off-by: Linjie Fu <linjie.fu at intel.com>
---
 libavcodec/libopenh264enc.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/libavcodec/libopenh264enc.c b/libavcodec/libopenh264enc.c
index c7ae5b1..57313b1 100644
--- a/libavcodec/libopenh264enc.c
+++ b/libavcodec/libopenh264enc.c
@@ -132,7 +132,7 @@ FF_ENABLE_DEPRECATION_WARNINGS
     param.fMaxFrameRate              = 1/av_q2d(avctx->time_base);
     param.iPicWidth                  = avctx->width;
     param.iPicHeight                 = avctx->height;
-    param.iTargetBitrate             = avctx->bit_rate;
+    param.iTargetBitrate             = avctx->bit_rate > 0 ? avctx->bit_rate : 2*1000*1000;
     param.iMaxBitrate                = FFMAX(avctx->rc_max_rate, avctx->bit_rate);
     param.iRCMode                    = RC_QUALITY_MODE;
     // QP = 0 is not well supported, so default to (1, 51)
@@ -335,6 +335,8 @@ static int svc_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
 }
 
 static const AVCodecDefault svc_enc_defaults[] = {
+    { "b",         "0"     },
+    { "g",         "120"   },
     { "qmin",      "-1"    },
     { "qmax",      "-1"    },
     { NULL },
-- 
2.7.4