From 35122bd93e7f3e08b42fbbed2e9b5c7ac5c1f4f5 Mon Sep 17 00:00:00 2001
From: Stefan Gehrer <stefan.gehrer@gmx.de>
Date: Mon, 15 Feb 2010 16:43:45 +0000
Subject: [PATCH] add heuristic to discern the old sample clips from streams
encoded with rm52j encoder, a marker_bit has been added in the I-Frame syntax
Originally committed as revision 21836 to svn://svn.ffmpeg.org/ffmpeg/trunk
---
libavcodec/cavs.h | 1 +
libavcodec/cavsdec.c | 9 +++++++++
2 files changed, 10 insertions(+)
diff --git a/libavcodec/cavs.h b/libavcodec/cavs.h
index 5ae664dd33b..fce55c3b715 100644
--- a/libavcodec/cavs.h
+++ b/libavcodec/cavs.h
@@ -160,6 +160,7 @@ typedef struct {
int aspect_ratio;
int mb_width, mb_height;
int pic_type;
+ int stream_revision; ///<0 for samples from 2006, 1 for rm52j encoder
int progressive;
int pic_structure;
int skip_mode_flag; ///< select between skip_count or one skip_flag per MB
diff --git a/libavcodec/cavsdec.c b/libavcodec/cavsdec.c
index 458fcf2bb57..5929c8e2fb8 100644
--- a/libavcodec/cavsdec.c
+++ b/libavcodec/cavsdec.c
@@ -483,6 +483,15 @@ static int decode_pic(AVSContext *h) {
h->pic_type = FF_I_TYPE;
if(get_bits1(&s->gb))
skip_bits(&s->gb,24);//time_code
+ /* old sample clips were all progressive and no low_delay,
+ bump stream revision if detected otherwise */
+ if((s->low_delay) || !(show_bits(&s->gb,9) & 1))
+ h->stream_revision = 1;
+ /* similarly test top_field_first and repeat_first_field */
+ else if(show_bits(&s->gb,11) & 3)
+ h->stream_revision = 1;
+ if(h->stream_revision > 0)
+ skip_bits(&s->gb,1); //marker_bit
}
/* release last B frame */
if(h->picture.data[0])
--
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