[vlc-devel] [PATCH] stream_filter: add ADF stream filter (Fixes #17501)

[Tristan Matthews]

On Tue, Oct 25, 2016 at 11:59 AM, Francois Cartegnie <fcvlcdev at free.fr> wrote:
> Le 25/10/2016 à 17:31, Filip Roséen a écrit :
>> Hi Francois,
>>
>> On 2016-10-25 17:18, Francois Cartegnie wrote:
>>
>>> Le 25/10/2016 à 06:56, Tristan Matthews a écrit :
>>>> +    /* Probe for XOR'd ID3 tag. */
>>>> +    if( memcmp( peek, "\x6B\x66\x11", 3 ) )
>>>> +        return VLC_EGENERIC;
>>>
>>> Being before any demuxer and packetizer,
>>> expect high rate of false positives.
>>
>>  - Why would this cause a *"high rate of false positives"?
>>
>> It is equivalent to a *demuxer* probing for the same data, and as far
>> as I could see when I looked up the *magic-bytes* used, there is no
>> *file-format* that is publically documented that uses that marker.
>
> Probing a single sequence is *weak*.
> and data has no alignment guarantee.
>
> Hence the demuxers priorities and the packetizer based demuxers and
> multiple frames probing for most audio codecs. (and libav has even more
> intensive probing)
>
> Putting this as stream filter gives it higher priority than any demuxer.
>
> Will break any non aligned, sync code based, if the stream starts with
> "\x6B\x66\x11" (raw video, raw audio, ts, ps...), where demux with low
> score would not.

I could reject urls not ending with .adf, not sure if that's
considered acceptable though.