[FFmpeg-user] how to display metadata?

[Pushkar Pradhan]

On Fri, Mar 25, 2011 at 11:43 AM, sean darcy <seandarcy2 at gmail.com> wrote:

> On 03/25/2011 02:37 PM, sean darcy wrote:
>
>> On 03/25/2011 11:27 AM, James Darnley wrote:
>>
>>> On 25/03/2011, sean darcy<seandarcy2 at gmail.com> wrote:
>>>
>>>> I've prepared a speech:
>>>>
>>>> ffmpeg -i "speech_1.wav" -metadata track="1" -metadata title="My Speech"
>>>> -acodec aac -ab 128000 -strict experimental speech_1.aac
>>>>
>>>> which seems to work fine, the track and title show on the console
>>>> output.
>>>>
>>>> But:
>>>>
>>>> ffmpeg -i speech.aac
>>>> Input #0, aac, from 'speech_1.aac':
>>>> Duration: 00:01:44.95, bitrate: 128 kb/s
>>>> Stream #0.0: Audio: aac, 44100 Hz, stereo, s16, 128 kb/s
>>>>
>>>
>>> That suggests the output format doesn't actually support metadata
>>>
>>
>> Huh? aac doesn't support metadata?
>>
>> It certainly looks like it does:
>>
>> ffmpeg -i "Track 1.wav" -metadata track=1 -metadata title="Test Track"
>> -acodec aac -ab 128000 -strict experimental Track_1.aac
>> ...............
>> Input #0, wav, from 'Track 1.wav':
>> Duration: 00:02:01.88, bitrate: 1411 kb/s
>> Stream #0.0: Audio: pcm_s16le, 44100 Hz, 2 channels, s16, 1411 kb/s
>> Output #0, adts, to 'Track_1.aac':
>> Metadata:
>> title : Test Track
>> track : 1
>> encoder : Lavf52.73.0
>> Stream #0.0: Audio: aac, 44100 Hz, 2 channels, s16, 128 kb/s
>> .......
>>
>> But:
>>
>> ffprobe Track_1.aac
>> Input #0, aac, from 'Track_1.aac':
>> Duration: 00:01:44.95, bitrate: 128 kb/s
>> Stream #0.0: Audio: aac, 44100 Hz, stereo, s16, 128 kb/s
>>
>>
>> So I guess the question is whether the aac encoder is creating the
>> metadata, or is ffprobe not reading it?
>>
>> And shouldn't EasyTag be able to read it if the metadata were there?
>>
>> sean
>>
>
> Well, it seems the aac encoder just isn't writing the metadata:
>
> ffmpeg -i "Track 1.wav" -metadata track=1 -metadata title="Test Track"
> -acodec libmp3lame -ab 128000  Track_1.mp3
> .........
>
> ffprobe Track_1.mp3
> Input #0, mp3, from 'Track_1.mp3':
>  Metadata:
>    TIT2            : Test Track
>    TRCK            : 1
>    TSSE            : Lavf52.73.0
>  Duration: 00:02:01.91, start: 0.000000, bitrate: 127 kb/s
>    Stream #0.0: Audio: mp3, 44100 Hz, 2 channels, s16, 128 kb/s
>
>
> sean
>
>
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>

MP3 definitely supports metadata in the form of ID3 Tags.
When I looked at the ADTS container format I didn't see a way to add
metadata: http://wiki.multimedia.cx/index.php?title=ADTS
Unless it can be prepended to the AAC samples itself?

To verify if the metadata is being injected in the AAC stream you can use a
hex editor and search for your string.

-- 
pushkar