[FFmpeg-devel] [PATCH] avcodec/libtwolame: fix mono default bitrate

[Paul B Mahol]

applied

On 11/1/19, James Cowgill <jcowgill at debian.org> wrote:
> As of libtwolame 0.4.0, 384 kbps is not accepted as a valid bitrate
> for encoding mono audio and the maximum bitrate is now halved to 192
> kbps to comply with the MP2 standard. Example error:
>
>     twolame_init_params(): 384kbps is an invalid bitrate for mono encoding.
>
> Adjust the default bitrate calculation to take this into account.
>
> Signed-off-by: James Cowgill <jcowgill at debian.org>
> ---
>  libavcodec/libtwolame.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/libavcodec/libtwolame.c b/libavcodec/libtwolame.c
> index 030f88868f..5ceb3d9f3f 100644
> --- a/libavcodec/libtwolame.c
> +++ b/libavcodec/libtwolame.c
> @@ -78,8 +78,12 @@ static av_cold int twolame_encode_init(AVCodecContext
> *avctx)
>      twolame_set_in_samplerate(s->glopts, avctx->sample_rate);
>      twolame_set_out_samplerate(s->glopts, avctx->sample_rate);
>
> -    if (!avctx->bit_rate)
> -        avctx->bit_rate = avctx->sample_rate < 28000 ? 160000 : 384000;
> +    if (!avctx->bit_rate) {
> +        if ((s->mode == TWOLAME_AUTO_MODE && avctx->channels == 1) ||
> s->mode == TWOLAME_MONO)
> +            avctx->bit_rate = avctx->sample_rate < 28000 ? 80000 : 192000;
> +        else
> +            avctx->bit_rate = avctx->sample_rate < 28000 ? 160000 : 384000;
> +    }
>
>      if (avctx->flags & AV_CODEC_FLAG_QSCALE || !avctx->bit_rate) {
>          twolame_set_VBR(s->glopts, TRUE);
> --
> 2.24.0.rc1
>
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