From: Gyan Doshi <ffmpeg@gyani.pro>
To: ffmpeg-devel@ffmpeg.org
Subject: Re: [FFmpeg-devel] [PATCH] libavcodec/libfdk-aacenc: Scale VBR mode with FF_QP2LAMBDA
Date: Wed, 22 Feb 2023 22:16:58 +0530
Message-ID: <74946841-b63a-d301-9013-bc32c33e31d2@gyani.pro> (raw)
In-Reply-To: <f7f5be18-7c32-48f8-2d9e-b09d61c2b38f@rothenpieler.org>
On 2023-02-22 10:12 pm, Timo Rothenpieler wrote:
> On 22.02.2023 17:33, Gyan Doshi wrote:
>> From
>>
>> fftools\ffmpeg_mux_init.c
>> 619: ost->enc_ctx->global_quality = FF_QP2LAMBDA * qscale
>>
>> Regards,
>> Gyan
>
> But that's only if you set the old qscale CLI options.
> If you set the global_quality option directly, there is no factor
> applied.
>
> By dividing by FF_QP2LAMBDA you break setting this value via
> global_quality, and instead add support for setting it via the old and
> pretty much abandoned qscale interface.
FWIW, that's what LAME does.
libavcodec\libmp3lame.c
119: lame_set_VBR_quality(s->gfp, avctx->global_quality /
(float)FF_QP2LAMBDA);
global_quality semantics seem overloaded. Maybe we should just redirect
user to priv vbr and error out in fdk init.
Regards,
Gyan
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next prev parent reply other threads:[~2023-02-22 16:47 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <63F57060.05FE3A.50083@loongson.cn>
2023-02-22 2:12 ` JonHGee
2023-02-22 16:09 ` Timo Rothenpieler
2023-02-22 16:33 ` Gyan Doshi
2023-02-22 16:42 ` Timo Rothenpieler
2023-02-22 16:46 ` Gyan Doshi [this message]
2023-02-22 17:15 ` Timo Rothenpieler
2023-02-22 18:49 ` Jonathan Gee
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