Re: [PATCH v3 0/5] ALSA: hda - hdmi: ATI/AMD multi-channel and HBR support

[Anssi Hannula <anssi.hannula@iki.fi>]

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29.10.2013 21:52, LANGLOIS Olivier PIS -EXT kirjoitti:
>>>
>>> Yep. I did manually verify that your EDID really claims AAC support,
>>> though. It could be wrong I guess, and the reported max_bitrate is
>>> suspiciously the same as for AC-3.
>>>
>>> If you want to try AAC bitstreaming, you can download this:
>>> http://onse.fi/files/testi.aac.lc.unconfirmed.spdif
>>> and play it back using:
>>> aplay -Dhdmi:CARD=Generic,DEV=0,AES0=6 -r44100 -f s16_le -c2 \
>>>     testi.aac.lc.unconfirmed.spdif
>>>
>>> (file unconfirmed as I don't have AAC HW)
>>
>> That looks like its playing something, but there's no sound at all. The receiver
>> claims there's a Dolby Digital stream active while that aplay command is
>> running... so yeah, looks like the EDID is lying.
>> (Same with another raw AAC LE file I just googled).

Note that compressed audio (except some cases of DTS) requires IEC-61937
encapsulation before output (this can be done e.g. with ffmpeg, "-f
spdif"). Not sure if the other file you got was like that, maybe.

But yes, looks like the receiver lies in EDID.

>> But on the good side, multichannel AC3 and DTS passthrough is working
>> flawlessly with XBMC ;)
>>
>> Thanks again,
>> Andre
> 
> Just throwing an idea like this. There is a small voice telling me that maybe HDMI receiver supporting AAC expect it wrapped inside ADTS packets rather than just raw AAC stream.

Yep, and my sample file is ADTS :)

> Also note that ffmpeg report formatting problem:
> 
> lano1106@hpmini ~ $ ffprobe testi.aac.lc.unconfirmed.spdif
> ffprobe version 2.1 Copyright (c) 2007-2013 the FFmpeg developers
>   built on Oct 29 2013 15:37:36 with gcc 4.8.2 (GCC)
>   configuration: --prefix=/usr --disable-debug --disable-static --enable-avresample --enable-dxva2 --enable-fontconfig --enable-gnutls --enable-gpl --enable-libass --enable-libfreetype --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librtmp --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libv4l2 --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxvid --enable-pic --enable-postproc --enable-runtime-cpudetect --enable-shared --enable-swresample --disable-vdpau --disable-vaapi --arch=native --cpu=native --enable-version3 --enable-x11grab
>   libavutil      52. 48.100 / 52. 48.100
>   libavcodec     55. 39.100 / 55. 39.100
>   libavformat    55. 19.104 / 55. 19.104
>   libavdevice    55.  5.100 / 55.  5.100
>   libavfilter     3. 90.100 /  3. 90.100
>   libavresample   1.  1.  0 /  1.  1.  0
>   libswscale      2.  5.101 /  2.  5.101
>   libswresample   0. 17.104 /  0. 17.104
>   libpostproc    52.  3.100 / 52.  3.100
> [spdif @ 0x8afc6b0] Invalid AAC packet in IEC 61937
> testi.aac.lc.unconfirmed.spdif: Invalid data found when processing input

FFmpeg bug. Patch attached (and sent to ffmpeg-devel@).

-- 
Anssi Hannula


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>From 24f271570ec3fb533126b22649651b52160ac232 Mon Sep 17 00:00:00 2001
From: Anssi Hannula <anssi.hannula@iki.fi>
Date: Tue, 29 Oct 2013 22:22:34 +0200
Subject: [PATCH] lavf/spdifdec: fix demuxing of AAC in IEC 61937

Return value of avpriv_aac_parse_header() is not checked correctly. Fix
it.

Signed-off-by: Anssi Hannula <anssi.hannula@iki.fi>
---
 libavformat/spdifdec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavformat/spdifdec.c b/libavformat/spdifdec.c
index 6984350..7da16c9 100644
--- a/libavformat/spdifdec.c
+++ b/libavformat/spdifdec.c
@@ -57,7 +57,7 @@ static int spdif_get_offset_and_codec(AVFormatContext *s,
         break;
     case IEC61937_MPEG2_AAC:
         init_get_bits(&gbc, buf, AAC_ADTS_HEADER_SIZE * 8);
-        if (avpriv_aac_parse_header(&gbc, &aac_hdr)) {
+        if (avpriv_aac_parse_header(&gbc, &aac_hdr) < 0) {
             if (s) /* be silent during a probe */
                 av_log(s, AV_LOG_ERROR, "Invalid AAC packet in IEC 61937\n");
             return AVERROR_INVALIDDATA;
-- 
1.8.1.5


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