[FFmpeg-devel] [PATCH] als in mp4

Justin Ruggles justin.ruggles
Sat Mar 21 12:46:04 CET 2009


Jai Menon wrote:
> On Sat, Mar 21, 2009 at 11:52 AM, Baptiste Coudurier
> <baptiste.coudurier at gmail.com> wrote:
>> Jai Menon wrote:
>>> On Sat, Mar 21, 2009 at 11:24 AM, Baptiste Coudurier
>>> <baptiste.coudurier at gmail.com> wrote:
>>>> Hi Jai,
>>>>
>>>> Jai Menon wrote:
>>>>> Hi,
>>>>>
>>>>> Attached :
>>>>>
>>>>> 1) demux als streams from mp4, als codec id and minor lavc version bump
>>>>> 2) mux als in to mp4, add isomedia type
>>>>>
>>>>> [...]
>>>>>
>>>>> @@ -1381,7 +1385,8 @@
>>>>>      uint8_t *buf;
>>>>>
>>>>>      for (i = 0; i < s->nb_streams; i++)
>>>>> -        if (mov->tracks[i].enc->flags & CODEC_FLAG_BITEXACT) {
>>>>> +        if (mov->tracks[i].enc->flags & CODEC_FLAG_BITEXACT ||
>>>>> +            mov->tracks[i].enc->codec_id == CODEC_ID_MP4ALS) {
>>>>>              return 0;
>>>>>          }
>>>>>
>>>> ???? Please explain :>
>>> ok :)
>>> the muxer currently writes out a userdata box, with a meta box inside
>>> (mp4 mode).
>>> The meta box has a itunes hdlr tag which again leads to problems. So the patch
>>> skips writing a udta box. maybe instead of this, we could write mov style udta.
>>> what do you suggest?
>>>
>>> btw, very sorry most of this looks like a hack, the reference codec
>>> mp4 parser has
>>> limitations.
>>>
>> Humm, sorry too hackish, where can I get this reference codec mp4 parser ?
> 
> http://www.nue.tu-berlin.de/forschung/projekte/lossless/mp4alsRM22.zip
> 
> i dunno if there is a newer version which is publicly available.
> maybe Justin knows?

RM22 is the latest.  Maybe you could try to fix whatever is weird about
it and send a patch to Tilman (liebchen at nue.tu-berlin.de).

-Justin




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