[FFmpeg-devel] [PATCH] als in mp4

[Robert Swain]

On 3/4/09 19:33, Alex Converse wrote:
> On Fri, Apr 3, 2009 at 1:58 PM, Baptiste Coudurier
> <baptiste.coudurier at gmail.com>  wrote:
>> Hi Jai,
>>
>> On 4/3/2009 3:00 AM, Jai Menon wrote:
>>> On 3/23/09, Baptiste Coudurier<baptiste.coudurier at gmail.com>  wrote:
>>>> Jai Menon wrote:
>>>>   >  On 3/23/09, Baptiste Coudurier<baptiste.coudurier at gmail.com>  wrote:
>>>>   >>  Jai Menon wrote:
>>>>   >>    >>  [...]
>>>>   >>
>>>>   >>    >>
>>>>   >>    >>  When were they initially set to the correct values?
>>>>   >>    >
>>>>   >>    >  stsd atom/box? i think
>>>>   >>    >
>>>>   >>
>>>>   >>
>>>>   >>  Hummm, stsd does not contain the correct sample number for everything
>>>>   >>    using 'mp4a' tag. Values are correct in 'esds' box.
>>>>   >
>>>>   >  Which means we should parse the extradata (in this case als specific
>>>>   >  conf) and get values from there? I can do this for als by maybe adding
>>>>   >  a new function to mpeg4audio.c.
>>>>
>>>>
>>>> I don't know how exactly ALS works, but it might use the
>>>>   AudioSpecificConfig like others, this code might belong to mpeg4audio.c,
>>>>   yes.
>>> So hows attached patch?
>>
>> I think the AOT_ALS case should be handled within mpeg4audio_get_config,
>> to retrieve correct sample_rate/channels if these are not set in
>> AudioSpecificCOnfig, I also beleve all AOT should be handled this way.
>>
>> I'd like mpeg4 audio expert/maintainer to comment on this.
>
> I can agree with that if Rob is OK with it.

Yup, I think we agree that that is the way forward. I say this because I 
think it is important for `ffmpeg -i infile.mp4` to report the stream 
properties (sample rate, channels, sample format).

I might even be so bold as to say that any container that cannot report 
these data for its contained streams is flawed. But I don't know too 
much about containers, nor if such exists. :)

Regards,
Rob