From 9cc6be9d27373eaaf04233d06fc01a244627f5d4 Mon Sep 17 00:00:00 2001
From: Baptiste Coudurier <baptiste.coudurier@gmail.com>
Date: Mon, 13 Nov 2006 11:30:26 +0000
Subject: [PATCH] add low delay forcing option for mpeg1/2 encoding
Originally committed as revision 7008 to svn://svn.ffmpeg.org/ffmpeg/trunk
---
libavcodec/mpegvideo.c | 15 +++++++++++++--
libavcodec/utils.c | 2 +-
2 files changed, 14 insertions(+), 3 deletions(-)
diff --git a/libavcodec/mpegvideo.c b/libavcodec/mpegvideo.c
index d286b12ce19..fda536c0689 100644
--- a/libavcodec/mpegvideo.c
+++ b/libavcodec/mpegvideo.c
@@ -1104,6 +1104,17 @@ int MPV_encode_init(AVCodecContext *avctx)
return -1;
}
+ if(s->flags & CODEC_FLAG_LOW_DELAY){
+ if (s->codec_id != CODEC_ID_MPEG2VIDEO && s->codec_id != CODEC_ID_MPEG1VIDEO){
+ av_log(avctx, AV_LOG_ERROR, "low delay forcing is only available for mpeg1/2\n");
+ return -1;
+ }
+ if (s->max_b_frames != 0){
+ av_log(avctx, AV_LOG_ERROR, "b frames cannot be used with low delay\n");
+ return -1;
+ }
+ }
+
if(s->avctx->thread_count > 1 && s->codec_id != CODEC_ID_MPEG4
&& s->codec_id != CODEC_ID_MPEG1VIDEO && s->codec_id != CODEC_ID_MPEG2VIDEO
&& (s->codec_id != CODEC_ID_H263P || !(s->flags & CODEC_FLAG_H263P_SLICE_STRUCT))){
@@ -1169,12 +1180,12 @@ int MPV_encode_init(AVCodecContext *avctx)
switch(avctx->codec->id) {
case CODEC_ID_MPEG1VIDEO:
s->out_format = FMT_MPEG1;
- s->low_delay= 0; //s->max_b_frames ? 0 : 1;
+ s->low_delay= !!(s->flags & CODEC_FLAG_LOW_DELAY);
avctx->delay= s->low_delay ? 0 : (s->max_b_frames + 1);
break;
case CODEC_ID_MPEG2VIDEO:
s->out_format = FMT_MPEG1;
- s->low_delay= 0; //s->max_b_frames ? 0 : 1;
+ s->low_delay= !!(s->flags & CODEC_FLAG_LOW_DELAY);
avctx->delay= s->low_delay ? 0 : (s->max_b_frames + 1);
s->rtp_mode= 1;
break;
diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index 789ad8e606d..2c7a76c1186 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -441,7 +441,7 @@ static const AVOption options[]={
{"truncated", NULL, 0, FF_OPT_TYPE_CONST, CODEC_FLAG_TRUNCATED, INT_MIN, INT_MAX, 0, "flags"},
{"naq", "normalize adaptive quantization", 0, FF_OPT_TYPE_CONST, CODEC_FLAG_NORMALIZE_AQP, INT_MIN, INT_MAX, V|E, "flags"},
{"ildct", "use interlaced dct", 0, FF_OPT_TYPE_CONST, CODEC_FLAG_INTERLACED_DCT, INT_MIN, INT_MAX, V|E, "flags"},
-{"low_delay", "force low delay", 0, FF_OPT_TYPE_CONST, CODEC_FLAG_LOW_DELAY, INT_MIN, INT_MAX, V|D, "flags"},
+{"low_delay", "force low delay", 0, FF_OPT_TYPE_CONST, CODEC_FLAG_LOW_DELAY, INT_MIN, INT_MAX, V|D|E, "flags"},
{"alt", "enable alternate scantable (mpeg2/mpeg4)", 0, FF_OPT_TYPE_CONST, CODEC_FLAG_ALT_SCAN, INT_MIN, INT_MAX, V|E, "flags"},
{"trell", "use trellis quantization", 0, FF_OPT_TYPE_CONST, CODEC_FLAG_TRELLIS_QUANT, INT_MIN, INT_MAX, V|E, "flags"},
{"global_header", "place global headers in extradata instead of every keyframe", 0, FF_OPT_TYPE_CONST, CODEC_FLAG_GLOBAL_HEADER, INT_MIN, INT_MAX, 0, "flags"},
--
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