[FFmpeg-devel] [PATCH] read metadata in FLAC demuxer
Justin Ruggles
justinruggles
Mon Oct 1 06:25:56 CEST 2007
Justin Ruggles wrote:
> Rich Felker wrote:
>> On Sun, Sep 30, 2007 at 08:52:35PM -0400, Justin Ruggles wrote:
>>> Rich Felker wrote:
>>>> On Sun, Sep 30, 2007 at 02:47:18PM -0400, Justin Ruggles wrote:
>>>>> Michael Niedermayer wrote:
>>>>>> On Sun, Sep 30, 2007 at 12:48:08AM -0400, Justin Ruggles wrote:
>>>>>>> Hi,
>>>>>>>
>>>>>>> Here is a patch to fix issue 187 in the FFmpeg Issue Tracker, "flac decoder
>>>>>>> fails with large metadata".
>>>>>>>
>>>>>>> For raw FLAC files, the metadata header(s) are read in the demuxer rather
>>>>>>> than the decoder. This correctly skips any irrelevant metadata blocks, and
>>>>>>> it also parses vorbiscomment info.
>>>>>> what happens with flac in avi and matroska ?
>>>>> True, it should be handled in those demuxers as well. And I do see your
>>>>> point as far as code duplication. I'm working on a better solution with
>>>>> shared code between the decoder and all the demuxers.
>>>> For other formats, metadata should not be in Ogg-specific format but
>>>> in whatever standard format the container uses.. I suspect that was
>>>> Michael's point..
>>> I see. Well the streaminfo data should be in the same format no matter
>>> what the container. Also, I believe a series of FLAC metadata blocks is
>>> standard for extradata in raw FLAC, Matroska, and other containers
>>> besides Ogg. AFAIK, Ogg is the only one which uses its own unique
>>> layout for FLAC metadata. The solution I'm working on takes this into
>>> account.
>> Matroska officially stores in-band FLAC-format metadata instead of
>> putting it in the Matroska headers where it belongs? I really doubt
>> that. If it's done it's probably some hack warez groups are doing and
>> not something officially sanctioned.. at least I can't imagine them
>> doing something THAT dumb..
>>
>> Rich
>
> I don't know a lot about Matroska, so I don't know where exactly the
> metadata is located, but as far as I can tell it is in the same format
> as raw FLAC. This is using mkvmerge. I did some tests and was able to
> locate the list of FLAC metadata blocks in exactly the same format as
> the original FLAC file. This doesn't mean that it's inline with the
> audio, but wherever it is, it is in the FLAC metadata format.
Using mkvinfo, it appears that the metadata blocks are located in
CodecPrivate.
-Justin
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