[MPlayer-users] latm re-initing sound doesn't downmix when channel conf changes

[Andy Furniss]

Carl Eugen Hoyos wrote:
> Andy Furniss <andyqos <at> ukfsn.org> writes:
>
>> Is it possible to re initialise sound "as if new" when
>> for example a latm aac stream switches from 2 to 6ch?
>>
>> This is quite common on UK DVB-T2 HD channels and it
>> seems depending on setup someone listening in stereo
>> will either just get L+R
>
> Isn't this expected behaviour or do I misunderstand?

No - I expect that mplayer will by default downmix 5.1 to 2 (or request 
2 channels from dec).

> Ie: If you cut the stereo part away from your sample
> and play the remaining 5.1 file with "mplayer file",
> does the output sound different from playing your
> original sample (including the channel number change)
> after the switch to 5.1 ?

Snipping 100k from the start behaves "correctly" - mplayer downmixes -

MPlayer SVN-r35933-4.7.2 (C) 2000-2013 MPlayer Team
CPU vendor name: AuthenticAMD  max cpuid level: 5
CPU: AMD Phenom(tm) II X4 965 Processor (Family: 16, Model: 4, Stepping: 3)
extended cpuid-level: 27
extended cache-info: 33587520
Detected cache-line size is 64 bytes
CPUflags:  MMX: 1 MMX2: 1 3DNow: 1 3DNowExt: 1 SSE: 1 SSE2: 1 SSE3: 1 
SSSE3: 0 SSE4: 0 SSE4.2: 0 AVX: 0
Compiled for x86 CPU with extensions: MMX MMX2 3DNow 3DNowExt SSE SSE2 
SSE3 CMOV
get_path('codecs.conf') -> '/home/andy/.mplayer/codecs.conf'
Reading optional codecs config file /home/andy/.mplayer/codecs.conf: No 
such file or directory
Reading optional codecs config file /usr/local/etc/mplayer/codecs.conf: 
No such file or directory
Using built-in default codecs.conf.
init_freetype
Using MMX (with tiny bit MMX2) Optimized OnScreenDisplay
get_path('fonts') -> '/home/andy/.mplayer/fonts'
Configuration: --enable-xvmc 
--extra-cflags=-I/home/andy/Src/Xorg-git/modular/include 
--extra-libs=-L/home/andy/Src/Xorg-git/modular/lib 
--extra-libs-mplayer=-L/home/andy/Src/Xorg-git/modular/lib
CommandLine: '-ao' 'alsa' '-mixer-channel' 'Master' '-v' 'snip-2chto51.latm'
Using nanosleep() timing
get_path('input.conf') -> '/home/andy/.mplayer/input.conf'
Reading optional input config file /home/andy/.mplayer/input.conf: No 
such file or directory
Reading optional input config file /usr/local/etc/mplayer/input.conf: No 
such file or directory
Falling back on default (hardcoded) input config
Setting up LIRC support...
mplayer: could not connect to socket
mplayer: No such file or directory
Failed to open LIRC support. You will not be able to use your remote 
control.
get_path('snip-2chto51.latm.conf') -> 
'/home/andy/.mplayer/snip-2chto51.latm.conf'

Playing snip-2chto51.latm.
get_path('sub/') -> '/home/andy/.mplayer/sub/'
[file] File size is 95644 bytes
STREAM: [file] snip-2chto51.latm
STREAM: Description: File
STREAM: Author: Albeu
STREAM: Comment: based on the code from ??? (probably Arpi)
libavformat version 54.63.104 (internal)
Configuration: --enable-gpl --enable-postproc
LAVF_check: raw LOAS/LATM
Checking for YUV4MPEG2
ASF_check: not ASF guid!
Checking for REAL
Checking for SMJPEG
Searching demuxer type for filename snip-2chto51.latm ext: .latm
Checking for Nullsoft Streaming Video
Checking for MOV
Checking for VIVO
header block 1 size: 127
AVS: avs_check_file - attempting to open file snip-2chto51.latm
AVS: File is too big, aborting...
Checking for PVA
Checking for MPEG-TS...
TRIED UP TO POSITION 68122, FOUND 47, packet_size= 0, SEEMS A TS? 0
Checking for LMLM4 Stream Format
Invalid packet in LMLM4 stream: ch=15487 size=3856831021
LMLM4 Stream Format not found
MPEG Stream reached EOF
ds_fill_buffer: EOF reached (stream: video)
MPEG packet stats: p100: 0  p101: 0 p1B6: 0 p12x: 0 sli: 0 a: 0 b: 0 c: 
0 idr: 0 sps: 0 pps: 0 PES: 0  MP3: 176, synced: 0
Not MPEG System Stream format... (maybe Transport Stream?)
MPEG Stream reached EOF
ds_fill_buffer: EOF reached (stream: video)
MPEG packet stats: p100: 0  p101: 0 p1B6: 0 p12x: 0 sli: 0 a: 0 b: 0 c: 
0 idr: 0 sps: 0 pps: 0 PES: 0  MP3: 176, synced: 3
Not MPEG System Stream format... (maybe Transport Stream?)
ds_fill_buffer: EOF reached (stream: video)
LAVF_check: raw LOAS/LATM
libavformat file format detected.
[latm @ 0x8bf7d80]File position before avformat_find_stream_info() is 0
[aac_latm @ 0x8c82240]initializing latmctx
[latm @ 0x8bf7d80]Estimating duration from bitrate, this may be inaccurate
[latm @ 0x8bf7d80]File position after avformat_find_stream_info() is 95644
==> Found audio stream: 0
======= WAVE Format =======
Format Tag: 20557 (0x504D)
Channels: 6
Samplerate: 48000
avg byte/sec: 0
Block align: 1
bits/sample: 0
cbSize: 2
Unknown extra header dump: [11] [b0]
==========================================================================
[lavf] stream 0: audio (aac_latm), -aid 0
LAVF: 1 audio and 0 video streams found
LAVF: build 3555176
Load subtitles in ./
get_path('sub/') -> '/home/andy/.mplayer/sub/'
==========================================================================
Opening audio decoder: [ffmpeg] FFmpeg/libavcodec audio decoders
dec_audio: Allocating 1536000 + 131072 = 1667072 bytes for output buffer.
FFmpeg's libavcodec audio codec
libavcodec version 54.92.100 (internal)
Configuration: --enable-gpl --enable-postproc
INFO: libavcodec "aac_latm" init OK!
lavc_audio: error
AUDIO: 48000 Hz, 6 ch, floatle, 0.0 kbit/0.00% (ratio: 0->1152000)
Selected audio codec: [fflatm] afm: ffmpeg (FFmpeg AAC in LATM)
==========================================================================
Building audio filter chain for 48000Hz/6ch/floatle -> 0Hz/0ch/??...
[libaf] Adding filter pan
[pan] Pan level from channel 0 to channel 0 = 0.400000
[pan] Pan level from channel 0 to channel 1 = 0.000000
[pan] Pan level from channel 1 to channel 0 = 0.000000
[pan] Pan level from channel 1 to channel 1 = 0.400000
[pan] Pan level from channel 2 to channel 0 = 0.200000
[pan] Pan level from channel 2 to channel 1 = 0.000000
[pan] Pan level from channel 3 to channel 0 = 0.000000
[pan] Pan level from channel 3 to channel 1 = 0.200000
[pan] Pan level from channel 4 to channel 0 = 0.300000
[pan] Pan level from channel 4 to channel 1 = 0.300000
[pan] Pan level from channel 5 to channel 0 = 0.100000
[pan] Pan level from channel 5 to channel 1 = 0.100000
Trying preferred audio driver 'alsa', options '[none]'
alsa-init: requested format: 48000 Hz, 2 channels, 1d
alsa-init: using ALSA 1.0.25
alsa-init: setup for 1/2 channel(s)
alsa-init: using device default
alsa-init: opening device in blocking mode
alsa-init: device reopened in blocking mode
[AO_ALSA] Format floatle is not supported by hardware, trying default.
alsa-init: got buffersize=96000
alsa-init: got period size 1416
alsa: 48000 Hz/2 channels/4 bpf/96000 bytes buffer/Signed 16 bit Little 
Endian
AO: [alsa] 48000Hz 2ch s16le (2 bytes per sample)
AO: Description: ALSA-0.9.x-1.x audio output
AO: Author: Alex Beregszaszi, Zsolt Barat <joy at streamminister.de>
AO: Comment: under development
Building audio filter chain for 48000Hz/6ch/floatle -> 48000Hz/2ch/s16le...
[libaf] Adding filter format
[format] Changing sample format from little-endian 32-bit float to 
little-endian 16-bit signed int
[format] Accelerated little-endian 32-bit float to little-endian 16-bit 
signed int conversion
[format] Changing sample format from little-endian 32-bit float to 
little-endian 16-bit signed int
[format] Accelerated little-endian 32-bit float to little-endian 16-bit 
signed int conversion
Video: no video
Freeing 0 unused video chunks.
Starting playback...
[libaf] Reallocating memory in module pan, old len = 0, new len = 43672
[libaf] Reallocating memory in module format, old len = 0, new len = 21833
Increasing filtered audio buffer size from 0 to 21824
Increasing filtered audio buffer size from 21824 to 43648
Increasing filtered audio buffer size from 43648 to 65472
Increasing filtered audio buffer size from 65472 to 87296
Increasing filtered audio buffer size from 87296 to 98048
A:   1.9 (01.8) of 0.0 (unknown)  1.7%
lavc_audio: error
A:   1.9 (01.8) of 0.0 (unknown)  1.7%
ds_fill_buffer: EOF reached (stream: audio)
A:   1.9 (01.8) of 0.0 (unknown)  1.7%
ds_fill_buffer: EOF reached (stream: audio)
A:   1.9 (01.9) of 0.0 (unknown)  1.7%
EOF code: 1

Uninit audio filters...
[libaf] Removing filter pan
[libaf] Removing filter format
Uninit audio: ffmpeg
alsa-uninit: pcm closed
vo: x11 uninit called but X11 not initialized..

Exiting... (End of file)