[FFmpeg-devel] [PATCH] FLAC parser

[Justin Ruggles]

Justin Ruggles wrote:

> Michael Chinen wrote:
> 
>> On Wed, Sep 29, 2010 at 2:51 AM, Justin Ruggles
>> <justin.ruggles at gmail.com> wrote:
>>> Justin Ruggles wrote:
>>>
>>>> Michael Chinen wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> On Mon, Sep 27, 2010 at 1:32 AM, Felipe Contreras
>>>>> <felipe.contreras at gmail.com> wrote:
>>>>>> 2010/9/26 M?ns Rullg?rd <mans at mansr.com>:
>>>>>>> Felipe Contreras <felipe.contreras at gmail.com> writes:
>>>>>>>
>>>>>>>> On Sun, Sep 26, 2010 at 1:58 PM, Michael Chinen <mchinen at gmail.com> wrote:
>>>>>>>>> On Sun, Sep 26, 2010 at 2:00 AM, Felipe Contreras
>>>>>>>>> [...]
>>>>>>>>>> Ah, I needed CONFIG_FLAC_PARSER.
>>>>>>>>> I would like to test this.  I am running configure without any mention
>>>>>>>>> of the parser.  How can I get it to go without CONFIG_FLAC_PARSER?
>>>>>>>> I guess --disable-parser=flac
>>>>>>>>
>>>>>>>>>> Since now the decoder doesn't work without the parser, wouldn't a
>>>>>>>>>> dependency should somehow be specified?
>>>>>>>>> Is this dependency undesirable?  I can look into getting both cases to
>>>>>>>>> work if so.
>>>>>>>> I don't know, but with your patches this stopped working:
>>>>>>>> ./configure --disable-everything --enable-decoder='flac'
>>>>>>>> --enable-demuxer='ogg,flac' --enable-protocol=file
>>>>>>>> --enable-encoder='pcm_s16le' --enable-muxer='wav'
>>>>>>>>
>>>>>>>> ffmpeg -i test.flac test.wav
>>>>>>> The demuxer probably needs the parser to find frame boundaries.  Can
>>>>>>> it play flac in ogg (where ogg provides the framing)?
>>>>>> I haven't tried this yet, but at least it doesn't seem to work with my
>>>>>> gst-av[1] stuff, so I think the problem is in the decoder itself.
>>>>> Any ogg related thing is definitely not supported in this
>>>>> parser/decoder (nor in the previous flacdec.c).
>>>>> flac in ogg is .ogg file right? - should it be handled by this parser/decoder?
>>>>>
>>>>> The patch isn't ready quite yet, but I'm working on it.
>>>> I can confirm that Ogg/FLAC doesn't work when you disable the parser,
>>>> but it does work when you enable the parser.  This is weird because the
>>>> Ogg demuxer doesn't even set st->need_parsing.  Plus, like Mans said,
>>>> Ogg shouldn't need to use the parser.  If Michael doesn't already have
>>>> it figured out, I'll see if I can find the problem this afternoon after
>>>> work.
>>> Ok, I take that back.  I thought I was testing an ogg file, but it was
>>> really a raw flac file.  I tested again with ogg/flac files made with
>>> both the flac commandline tool and with ffmpeg and the previous patch,
>>> including changes to flacdec.c work just fine for me.  Can anyone else
>>> reproduce the problems that Felipe is having?  Or can you give more info
>>> Felipe?
>> When I configure with --disable-parser=flac
>>
>> if I run files generated with "ffmpeg -i a.wav -acodec flac a.ogg"
>> The decoder works fine.
>>
>> but if I try to do Yesterday.ogg (flac in ogg sample) it fails
>>
>> I get a fail:
>> [NULL @ 0x1002600] Probed with size=2048 and score=100
>> [flac @ 0x1004000] invalid frame header: frame sync error
>> [flac @ 0x1004000] decode_frame() failed
>> [flac @ 0x1004000] invalid frame header: frame sync error
>> [flac @ 0x1004000] decode_frame() failed
>> [flac @ 0x1004000] invalid frame header: frame sync error
>> [flac @ 0x1004000] decode_frame() failed
>> (etc)
> 
> Yesterday.ogg is an "old style" (pre libFLAC 1.1.1) Ogg/FLAC file.  To
> quote the "ogg mapping" page on the FLAC website:
> 
> "It should also be noted that support for encapsulating FLAC in Ogg has
> been present in the FLAC tools since version 1.0.1. However, the
> mappings used were never formalized and have insurmountable problems.
> For that reason, Ogg FLAC streams created with flac versions before
> 1.1.1 should be decoded and re-encoded with flac 1.1.1 or later (flac
> 1.1.1 can decode all previous Ogg FLAC files, but files made prior to
> 1.1.0 don't support seeking). Since the support for Ogg FLAC before FLAC
> 1.1.1 was limited, we hope this will not result in too much inconvenience."
> 
>> metaflac --list ~/Desktop/Yesterday.ogg
> ...
>   vendor string: reference libFLAC 1.1.0 20030126
> 
> We should still try to support those old files, but that is a completely
> different issue I think.  What I get is a few frame sync errors, then a
> bunch of errors that the channel layout cannot change mid-stream.  So
> the first few packets are likely header packets that are not identified
> as such.  The remaining packets seem correct.  That shouldn't be too
> hard to work around.

I just committed a fix to the FLAC decoder that should allow it to work
with this file after the FLAC parser is added and the current decoder
buffering hack is removed.

-Justin