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ffmpeg: add xbmc patch

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This commit is contained in:
Stefan Saraev 2013-12-20 19:39:07 +02:00
parent f6e5057df0
commit e453ba4c45
1 changed files with 67 additions and 0 deletions
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67
packages/multimedia/ffmpeg/patches/ffmpeg-0061-ffmpeg-backport-avcodec-aacdec-default-to-non-wide-7.patch Normal file
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@ -0,0 +1,67 @@
From 59f16d529fdcb4c5db53ce3bd289aa8148a13de4 Mon Sep 17 00:00:00 2001
From: Anssi Hannula <anssi.hannula@iki.fi>
Date: Tue, 17 Dec 2013 23:04:31 +0200
Subject: [PATCH] [ffmpeg] - backport - avcodec/aacdec: default to non-wide 7.1
in non-strict mode
Upstream commit e10fccf62a36e09b54ad6ea3d5fa6638f298d5ae, for
http://trac.xbmc.org/ticket/13758.
AAC specification has 7.1(wide) as a default layout for 8-channel
streams (channel config 7). However, at least Nero AAC encoder encodes
non-wide 7.1 streams using the default channel config 7, mapping the
side channels of the original audio stream to the second
AAC_CHANNEL_FRONT pair in the AAC stream. Similarly, e.g. FAAD decodes
the second AAC_CHANNEL_FRONT pair as side channels, therefore decoding
the incorrect streams as if they were correct (and as the encoder
intended).
FFmpeg currently decodes such files by-the-spec, i.e. after decoding the
original front pair will be in AV_CH_FRONT_x_OF_CENTER and the original
side pair will be in AV_CH_FRONT_x.
As actual intended 7.1(wide) streams are very rare while misencoded 7.1
files actually exist in the wild, default to assuming a 7.1 layout was
intended unless in strict mode.
Fixes playback of e.g. 8_Channel_ID.m4a in samples.
Signed-off-by: Anssi Hannula <anssi.hannula@iki.fi>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
---
libavcodec/aacdec.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/libavcodec/aacdec.c b/libavcodec/aacdec.c
index 7a871c4..12dbfcf 100644
--- a/libavcodec/aacdec.c
+++ b/libavcodec/aacdec.c
@@ -505,6 +505,25 @@ static int set_default_channel_config(AVCodecContext *avctx,
}
*tags = tags_per_config[channel_config];
memcpy(layout_map, aac_channel_layout_map[channel_config-1], *tags * sizeof(*layout_map));
+
+ /*
+ * AAC specification has 7.1(wide) as a default layout for 8-channel streams.
+ * However, at least Nero AAC encoder encodes 7.1 streams using the default
+ * channel config 7, mapping the side channels of the original audio stream
+ * to the second AAC_CHANNEL_FRONT pair in the AAC stream. Similarly, e.g. FAAD
+ * decodes the second AAC_CHANNEL_FRONT pair as side channels, therefore decoding
+ * the incorrect streams as if they were correct (and as the encoder intended).
+ *
+ * As actual intended 7.1(wide) streams are very rare, default to assuming a
+ * 7.1 layout was intended.
+ */
+ if (channel_config == 7 && avctx->strict_std_compliance < FF_COMPLIANCE_STRICT) {
+ av_log(avctx, AV_LOG_INFO, "Assuming an incorrectly encoded 7.1 channel layout"
+ " instead of a spec-compliant 7.1(wide) layout, use -strict %d to decode"
+ " according to the specification instead.\n", FF_COMPLIANCE_STRICT);
+ layout_map[2][2] = AAC_CHANNEL_SIDE;
+ }
+
return 0;
}
--
1.8.1.5