[FFmpeg-devel] [RFC] special "broken DV" demuxer

Baptiste Coudurier baptiste.coudurier
Wed Mar 11 10:14:44 CET 2009

Hi Reimar,

On 3/10/2009 1:54 AM, Reimar D?ffinger wrote:
> On Tue, Mar 10, 2009 at 01:21:52AM -0700, Baptiste Coudurier wrote:
>> On 3/10/2009 1:18 AM, Reimar D?ffinger wrote:
>>> On Mon, Mar 09, 2009 at 04:40:13PM -0700, Roman V Shaposhnik wrote:
>>>> On Sun, 2009-03-08 at 18:28 +0100, Reimar D?ffinger wrote:
>>>>> in our samples there is one horribly broken DV file:
>>>>> http://samples.mplayerhq.hu/V-codecs/DVSD/pond.dv
>>>>> As far as I can tell (with my limited understanding of the DV format)
>>>>> this is basically some DV headers "randomly" placed and then
>>>>> the data essential to decoding DV written over it.
>>>> Huh? pond.dv used to be a perfectly good DV sample.
>>> My judgement is limited since I never read the DV spec, but I find it
>>> hard to believe that a file without header, audio or video sections,
>>> half of the bits marked as "reserved, must be 1" in our encoder set to 0
>>> etc. qualifies as "perfectly good".
>> It seems file is weird indeed.
>> However, it seems this file has some pattern which could be recognized
>> around offset 0x50 (3F 07 00), and after this file seems ok.
> Here is a patch that uses this. But, compared to my other suggestion it
> might not work for DV files that are broken differently (the section we
> are checking for does not seem important, so I would expect there will
> be DV files that lack it, even if it violates the specification).
> Also it requires seeking.

In fact, it seems the demuxer seeks anyway in read_header, so I guess
the patch should be fine.

Baptiste COUDURIER                              GnuPG Key Id: 0x5C1ABAAA
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