[x264-devel] bug report

[Henrik Gramner]

On Mon, Jun 24, 2019 at 5:07 PM Attila József <user1894 at gmail.com> wrote:
>
> Hi.
>
> I want to report an interesting bug.
>
> I use ffmpeg with x264 lib for lot of tasks. Nowadays, i realize that some encoded video is not playable on some set-top boxes anymore. I started  lokking for the error. After lot of compilling, and testing, i found exactly one commit, that related to this problem. Before that commit, encoded video works perfectly on every device. After this, only with baseline profile, and/or with interlaced fields.
>
> the commit:
> ----
> 92d36908cbafd2a6edf7e61d69f341027b57f6f8
>
> Author: Yusuke Nakamura <muken.the.vfrmaniac at gmail.com>
> Date:   Mon Apr 9 11:01:28 2018 +0900
>
>     Signal Progressive and Constrained profiles
>
>     Progressive High, Constrained High, and Progressive High 10.
>
>     Even in Main profile, constraint_set4_flag is now set to 1 if progressive,
>     and constraint_set5_flag is set to 1 if no B-slices are present.
> ----
>
> According to my experiences, many amiko boxes affected to this problem, like:
> amiko mini hd
> amiko 8140c se
> amiko 8142 twin c
> amiko impulse
> Amiko Mini HD265
>
> Please help me.

It's an issue with your decoder(s) as they fail if one of the
previously reserved bits is now 1 instead of 0 which they really
should be ignoring, so you should probably send a bug report to the
manufacturer.

It seems there are a few different devices with the same issue though,
so maybe we should just revert this change since I don't have much
faith in decoder manufactures fixing bugs, especially for older
products.