[FFmpeg-devel] [PATCH] Fix SPDIF detection score

[Denis Shulyaka]

Hi all,

This is a kind reminder.

Best regards,
Denis Shulyaka

ср, 16 июн. 2021 г. в 02:07, Denis Shulyaka <shulyaka at gmail.com>:

> Sorry for not giving the proper description! Here it is:
> The spdif is based on blocks with fixed length, each block starts with a
> sync word. It matters how many sync words we find during probe and whether
> we find them in expected place. The SPDIF_MAX_OFFSET constant is the
> maximum supported block side. When we find a sync word, we shift the upper
> boundary of the search area (probe_end) by SPDIF_MAX_OFFSET, however this
> boundary is exclusive (the condition in the loop is "strictly less"), and
> when the actual block size matches the max supported block size, then the
> second sync word appears to be outside of the search area by 1 byte. As a
> result, we find only one sync word and return an incorrect score
> (AVPROBE_SCORE_EXTENSION / 4 instead of AVPROBE_SCORE_MAX). The fix gives 1
> more byte to the search area to allow finding the subsequent sync word.
> To reproduce the issue you would need a sample with SPDIF_MAX_OFFSET
> (16384) block size (probably AAC with samples = 4096). I do not have such
> sample as I found this issue while working on a new codec support.
>
> ср, 16 июн. 2021 г., 01:18 Hendrik Leppkes <h.leppkes at gmail.com>:
>
>> On Tue, Jun 15, 2021 at 12:52 PM Denis Shulyaka <shulyaka at gmail.com>
>> wrote:
>> >
>> > Hi! How do I ask for a review? I am new here.
>> >
>>
>> A short explanation of what the problem is and why this change fixes
>> it would help us to understand and evaluate the patch - and generally
>> makes for better patches, as any future reader will be able to look up
>> where the +1 came from and why it should be there. :)
>>
>> - Hendrik
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>

-- 
Best regards,
Denis Shulyaka