[FFmpeg-user] QUESTION ABOUT VIDEO CODECS : LIBX264 vs LIBX265

[Dennis Mungai]

On Sun, 31 Mar 2024 at 19:15, Hervé ANSELME <
hervea95-at-hotmail.com at ffmpeg.org> wrote:

> Hi all,
>
> I have a question about re-encoding a source video having libx264 video
> codec.
>
> Is there any advantage(s) to re-encode with the libx265, which is supposed
> to give better result than libx264 ?
>
> In other words, re-encoding with the x265 codec for the final video : can
> it improve the final video quality, compared to the source video, when the
> source video is encoded with x264 ?
>
> Thanks for your answers.
>
> Regards,
> HA
>

Quick answers:

Is there any advantage(s) to re-encode with libx265, which is supposed to
give better results than libx264 ?

Yes, *if* the target bitrate(s) are expected to be lower to fit within
specific constraints, such as live streaming and archival, and with an
acceptable trade off in quality for saved bandwidth & storage.
Even then, the target encoder(s) must be tuned specifically for the
workload(s) in question.

In other words, re-encoding with the x265 codec for the final video : can
it improve the final video quality, compared to the source video, when the
source video is encoded with x264 ?

No, video quality will actually degrade. Both are lossy codecs by design.