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[FFmpeg-devel,v5,2/5] lavc/libopenh264enc: add default gop size and bit rate

Message ID 1588065363-7104-3-git-send-email-linjie.fu@intel.com
State Superseded
Headers show
Series enhancement for libopenh264
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andriy/default pending
andriy/make success Make finished
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Commit Message

Fu, Linjie April 28, 2020, 9:16 a.m. UTC
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 to -1 to check whether it's specified
by user explicitly.

Use 2Mbps bitrate as nvenc sugguested, and leave gop size
untouched in libopenh264.

Signed-off-by: Linjie Fu <linjie.fu@intel.com>
---
 libavcodec/libopenh264enc.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/libavcodec/libopenh264enc.c b/libavcodec/libopenh264enc.c
index 1b6b53a..0951412 100644
--- a/libavcodec/libopenh264enc.c
+++ b/libavcodec/libopenh264enc.c
@@ -37,6 +37,8 @@ 
 #define SM_SIZELIMITED_SLICE SM_DYN_SLICE
 #endif
 
+#define TARGET_BITRATE_DEFAULT 2*1000*1000
+
 typedef struct SVCContext {
     const AVClass *av_class;
     ISVCEncoder *encoder;
@@ -132,7 +134,7 @@  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 : TARGET_BITRATE_DEFAULT;
     param.iMaxBitrate                = FFMAX(avctx->rc_max_rate, avctx->bit_rate);
     param.iRCMode                    = RC_QUALITY_MODE;
     // QP = 0 is not well supported, so clip to (1, 51)
@@ -148,7 +150,8 @@  FF_ENABLE_DEPRECATION_WARNINGS
     param.bEnableFrameSkip           = s->skip_frames;
     param.bEnableLongTermReference   = 0;
     param.iLtrMarkPeriod             = 30;
-    param.uiIntraPeriod              = avctx->gop_size;
+    if (avctx->gop_size)
+        param.uiIntraPeriod          = avctx->gop_size;
 #if OPENH264_VER_AT_LEAST(1, 4)
     param.eSpsPpsIdStrategy          = CONSTANT_ID;
 #else
@@ -337,6 +340,8 @@  static int svc_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
 }
 
 static const AVCodecDefault svc_enc_defaults[] = {
+    { "b",         "0"     },
+    { "g",         "-1"    },
     { "qmin",      "-1"    },
     { "qmax",      "-1"    },
     { NULL },