[FFmpeg-devel] [PATCH] lavf/avienc: New AVOption write_keyframe_palette

Ronald S. Bultje rsbultje at gmail.com
Tue Mar 8 13:43:13 CET 2016


Hi Mats,

On Mon, Mar 7, 2016 at 8:59 PM, Mats Peterson <
matsp888-at-yahoo.com at ffmpeg.org> wrote:

> On 03/07/2016 07:48 PM, Mats Peterson wrote:
>
>> On 03/07/2016 07:43 PM, Mats Peterson wrote:
>>
>>> Here's a somewhat experimental patch with a new AVOption
>>> write_keyframe_palette that allows you to write the palette to every
>>> keyframe. It is disabled by default, but it is needed for any file that
>>> contains palette changes.
>>>
>>>
>> It is needed in order to switch palette properly when seeking, that is.
>>
>>
> It's interesting to note that Windows Media Player doesn't need xxpc
> chunks at keyframes in order to seek properly in the following original
> file from Sierra's King's Quest VI. I have of course no idea how they solve
> that.
>
> This original file doesn't work properly in FFplay for some reason. It
> generates "stream_ptr out of bounds" messages at the locations of the xxpc
> chunks.
>
> File:
> https://drive.google.com/open?id=0B3_pEBoLs0faaFY0ME92SDA1VEU


Please don't wrote so many messages in response to yourself.

If you want, I can look at the file. My assumption is that it either
indexes or otherwise caches the xxpc chunks so it knows what the last xxpc
before-or-on each keyframe seekpoint is. That should be trivial to do in
our demuxer also.

Ronald


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