[FFmpeg-devel] [PATCH] libavcodec/ccaption_dec: remove unnecessary buffering of closed caption packets

Anshul anshul.ffmpeg at gmail.com
Fri Jan 8 13:26:29 CET 2016

On 8 January 2016 5:27:37 pm IST, "Clément Bœsch" <u at pkh.me> wrote:
>On Fri, Jan 08, 2016 at 05:24:15PM +0530, Anshul wrote:
>> On 6 January 2016 1:55:27 am IST, "Clément Bœsch" <u at pkh.me> wrote:
>> >On Sun, Jan 03, 2016 at 01:07:15PM +0100, Clément Bœsch wrote:
>> >[...]
>> >> This indeed LGTM, but I'm not the maintainer.
>> >> 
>> >
>> >OK I finally understood why it's done that way:
>> >alters the pkt data, but the decoder isn't supposed to do that.
>> >
>> >So this patch is actually incorrect in this state.
>> I did not knew, what could be the disadvantage of changing pkt data,
>> changed it to save some CPU cycles.
>The packet is considered read-only for the decoder. It appears not to
>marked as const for whatever bad reason.
>But what CPU cycles would you be saving anyway here? I don't see what
>operation you are saving.

Not much, just bitwise operations to discard parity bit, every time for conversion and comparison.


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