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From: Jaka Bac <jakabac@gmail.com>
To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org>
Subject: [FFmpeg-devel] qmax limit 28 in mpegvideo_enc.c
Date: Thu, 15 Sep 2022 14:00:01 +0200
Message-ID: <CAPQ1XRFv3cb9QhLRo6vW2SHXjgU3gWMn48_tv-AA_+Zu1fBqJA@mail.gmail.com> (raw)

Hello,

mpegvideo_enc.c contains this check in ff_mpv_encode_init:

    if (s->q_scale_type == 1) {
        if (avctx->qmax > 28) {
            av_log(avctx, AV_LOG_ERROR,
                   "non linear quant only supports qmax <= 28 currently\n");
            return AVERROR_PATCHWELCOME;
        }
    }

This was added in:
avcodec/mpeg12enc: extend QP range to 28 for non linear quantizers
https://github.com/FFmpeg/FFmpeg/commit/bf2474c74f2c0b956c069f50483c7d104d856d8b


After a while there was another commit:
avcodec/mpeg12enc: Basic support for encoding non even QPs for
-non_linear_quant 1
https://github.com/FFmpeg/FFmpeg/commit/58fe57d5a05ad8d15c320b2bd163debbc412bdd3

I may be completely wrong, but to me it looks like that the second commit
lifts the "qmax <= 28 restriction".
Or am I missing something?

Thanks,
Jaka
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                 reply	other threads:[~2022-09-15 12:00 UTC|newest]

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