[FFmpeg-devel] [PATCH] SHOUTcast HTTP Support

Michael Niedermayer michaelni
Sun Feb 28 21:00:17 CET 2010


On Sun, Feb 28, 2010 at 12:38:50PM -0500, MIcah Galizia wrote:
> On 10-02-28 11:43 AM, Michael Niedermayer wrote:
>
> [...]
>
>>> I have moved the probe loop into its own method and it is working for ogg
>>> (because ogg_probe is so simple), but it causes a problem for mp3 streams
>>> due to the minimum score we require when probing the stream. In utils.c,
>>> unless we have reached the max probe buffer size, score_max is 25 and
>>> unless the demuxer returns a probe score>  25, that demuxer will not be
>>> used.
>>>
>>> The mp3 demuxer does not return>  25 unless max_frames>  500 or
>>> first_frames>  4.  I don't know anything about those frames (or what they
>>> do), but I have observed that those conditions are not met until we have
>>> read 256Kb (on a local file and a stream without icy).
>>
>> I think ive fixed this, if not i need the mp3 file that is failing to be
>> detected quicker
>
> I just pulled down a clean version of ffmpeg from svn and for my local mp3 
> file, first_frames is no longer zero each time so the probe succeeds much 
> faster (buffer size is 1<<13). However, the problem still exists for the 
> streams I have been testing with. Try playing 
> http://shoutcast1.cbcradio3.com (or chronix radio at 
> http://205.188.215.225:8012).  Both of these still require a buffer size of 
> 1<<18 and reconnect three times. Also, first_frame is always zero for these 
> streams.
>
> After updating my modified version of ffmpeg with icy turned on, the 
> results are event worse (I suspect because of the metadata) and the probe 
> keeps failing.

the probe code should work fine for mp3.
if not, thats a bug and if you upload a mp3 file for which it fails i can
look into this.
a wget of the urls above does not return mp3 (theres html & icy stuff
interleaved). Its of course clear that feeding sliced and diced mp3 is
not probed which high score. mp3 in avi is not mp3 and we wouldnt want it
detected as such


[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Breaking DRM is a little like attempting to break through a door even
though the window is wide open and the only thing in the house is a bunch
of things you dont want and which you would get tomorrow for free anyway
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