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Add support for MPEG-4 ALS to the MP4 demuxer and FFmpeg wrapper. 

MPEG-4 ALS is a pure losses audio codec from MPEG. Like other MPEG-4
Audio variants it's muxed into the MP4 container with Object Type
Indication 0x40 followed by its Audio Object Type (36).

Sample:
http://streams.videolan.org/Mpeg_Conformance/ftp.iis.fhg.de/mpeg4audio-conformance/compressedMp4/als_00_2ch48k16b.mp4

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>
This commit is contained in:
Alex Converse 2010-03-24 00:08:53 -04:00 committed by Jean-Baptiste Kempf
parent 9f72dd7fb3
commit df7e8cf916
4 changed files with 12 additions and 0 deletions
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1
include/vlc_fourcc.h
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@ -194,6 +194,7 @@
/* Audio codec */
#define VLC_CODEC_MPGA VLC_FOURCC('m','p','g','a')
#define VLC_CODEC_MP4A VLC_FOURCC('m','p','4','a')
#define VLC_CODEC_ALS VLC_FOURCC('a','l','s',' ')
#define VLC_CODEC_A52 VLC_FOURCC('a','5','2',' ')
#define VLC_CODEC_EAC3 VLC_FOURCC('e','a','c','3')
#define VLC_CODEC_DTS VLC_FOURCC('d','t','s',' ')

1
modules/codec/avcodec/fourcc.c
View File

@ -296,6 +296,7 @@ static const struct
{ VLC_CODEC_MPGA, CODEC_ID_MP3, AUDIO_ES },
{ VLC_CODEC_MP4A, CODEC_ID_AAC, AUDIO_ES },
{ VLC_CODEC_ALS, CODEC_ID_MP4ALS, AUDIO_ES },
{ VLC_CODEC_INTERPLAY_DPCM, CODEC_ID_INTERPLAY_DPCM, AUDIO_ES },

6
modules/demux/mp4/mp4.c
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@ -1727,6 +1727,12 @@ static int TrackCreateES( demux_t *p_demux, mp4_track_t *p_track,
break;
case( 0x40):
p_track->fmt.i_codec = VLC_FOURCC( 'm','p','4','a' );
if( p_decconfig->i_decoder_specific_info_len >= 2 &&
p_decconfig->p_decoder_specific_info[0] == 0xF8 &&
(p_decconfig->p_decoder_specific_info[1]&0xE0) == 0x80 )
{
p_track->fmt.i_codec = VLC_CODEC_ALS;
}
break;
case( 0x60):
case( 0x61):

4
src/misc/fourcc.c
View File

@ -875,6 +875,10 @@ static const entry_t p_list_audio[] = {
A("mp4a"),
A("aac "),
/* ALS audio */
B(VLC_CODEC_ALS, "MPEG-4 Audio Lossless (ALS)"),
A("als "),
/* 4X Technologies */
B(VLC_CODEC_ADPCM_4XM, "4X Technologies Audio"),
A("4xma"),