[FFmpeg-user] audio only AAC in HLS

[Guido Holz]

Hi,

I'm trying to encode a aac file that is playable in an embedded player. All
I have tried doesn't work.
I've downloaded an example from a radio-live-stream.
auido.aac is my generated AAC file and the long one is what I've copied
from the live tream

\> ffmpeg  -i audio_root.aac -c:a libfdk_aac -b:a 64k  audio.aac

\> ffmpeg -i audio.aac
Input #0, aac, from 'audio.aac':
  Duration: 00:04:35.31, bitrate: 63 kb/s
    Stream #0:0: Audio: aac (LC), 44100 Hz, stereo, fltp, 63 kb/s

\> ffmpeg  -i
../../tmp/media_w370587926_b160000_ao_slen_t64RW5nbGlzaA\=\=_4.aac
Input #0, aac, from
'../../tmp/media_w370587926_b160000_ao_slen_t64RW5nbGlzaA==_4.aac':
  Duration: 00:00:05.80, bitrate: 165 kb/s
    Stream #0:0: Audio: aac (LC), 44100 Hz, stereo, fltp, 165 kb/s

\> ffprobe -v quiet -print_format json -show_format -show_streams audio.aac
{
    "streams": [
        {
            "index": 0,
            "codec_name": "aac",
            "codec_long_name": "AAC (Advanced Audio Coding)",
            "profile": "LC",
            "codec_type": "audio",
            "codec_time_base": "1/44100",
            "codec_tag_string": "[0][0][0][0]",
            "codec_tag": "0x0000",
            "sample_fmt": "fltp",
            "sample_rate": "44100",
            "channels": 2,
            "channel_layout": "stereo",
            "bits_per_sample": 0,
            "r_frame_rate": "0/0",
            "avg_frame_rate": "0/0",
            "time_base": "1/28224000",
            "duration_ts": 7770301271,
            "duration": "275.308293",
            "bit_rate": "63738",
            "disposition": {
                "default": 0,
                "dub": 0,
                "original": 0,
                "comment": 0,
                "lyrics": 0,
                "karaoke": 0,
                "forced": 0,
                "hearing_impaired": 0,
                "visual_impaired": 0,
                "clean_effects": 0,
                "attached_pic": 0
            }
        }
    ],
    "format": {
        "filename": "audio.aac",
        "nb_streams": 1,
        "nb_programs": 0,
        "format_name": "aac",
        "format_long_name": "raw ADTS AAC (Advanced Audio Coding)",
        "duration": "275.308293",
        "size": "2193450",
        "bit_rate": "63738",
        "probe_score": 51
    }
}

\>ffprobe -v quiet -print_format json -show_format -show_streams
../../tmp/media_w370587926_b160000_ao_slen_t64RW5nbGlzaA\=\=_4.aac
{
    "streams": [
        {
            "index": 0,
            "codec_name": "aac",
            "codec_long_name": "AAC (Advanced Audio Coding)",
            "profile": "LC",
            "codec_type": "audio",
            "codec_time_base": "1/44100",
            "codec_tag_string": "[0][0][0][0]",
            "codec_tag": "0x0000",
            "sample_fmt": "fltp",
            "sample_rate": "44100",
            "channels": 2,
            "channel_layout": "stereo",
            "bits_per_sample": 0,
            "r_frame_rate": "0/0",
            "avg_frame_rate": "0/0",
            "time_base": "1/28224000",
            "duration_ts": 163676160,
            "duration": "5.799184",
            "bit_rate": "165375",
            "disposition": {
                "default": 0,
                "dub": 0,
                "original": 0,
                "comment": 0,
                "lyrics": 0,
                "karaoke": 0,
                "forced": 0,
                "hearing_impaired": 0,
                "visual_impaired": 0,
                "clean_effects": 0,
                "attached_pic": 0
            }
        }
    ],
    "format": {
        "filename":
"../../tmp/media_w370587926_b160000_ao_slen_t64RW5nbGlzaA==_4.aac",
        "nb_streams": 1,
        "nb_programs": 0,
        "format_name": "aac",
        "format_long_name": "raw ADTS AAC (Advanced Audio Coding)",
        "duration": "5.799184",
        "size": "119953",
        "bit_rate": "165475",
        "probe_score": 51
    }
}

I can't see any differences.. but I know I have to add ID3 and ADTS to the
aac-files.

\>exiftool audio.aac
ExifTool Version Number         : 9.46
File Name                       : audio.aac
Directory                       : .
File Size                       : 2.1 MB
File Modification Date/Time     : 2016:02:17 13:12:10+01:00
File Access Date/Time           : 2016:02:17 13:12:47+01:00
File Inode Change Date/Time     : 2016:02:17 13:12:10+01:00
File Permissions                : rw-rw-r--
Error                           : Unknown file type

\>exiftool
../../tmp/media_w370587926_b160000_ao_slen_t64RW5nbGlzaA\=\=_4.aac
ExifTool Version Number         : 9.46
File Name                       :
media_w370587926_b160000_ao_slen_t64RW5nbGlzaA==_4.aac
Directory                       : ../../tmp
File Size                       : 117 kB
File Modification Date/Time     : 2015:12:14 23:17:45+01:00
File Access Date/Time           : 2016:02:17 12:27:03+01:00
File Inode Change Date/Time     : 2016:02:13 21:33:53+01:00
File Permissions                : rw-rw-r--
File Type                       : MP3
MIME Type                       : audio/mpeg
ID3 Size                        : 73
Private                         : (Binary data 8 bytes, use -b option to
extract)


You see ID3 and mp3 as file type? What command can I use to see differences
for ID3 and ADTS?

thanks