On 1/22/2018 3:16 PM, mrdeg...@gmail.com wrote:
> From: Menno <mrdeg...@gmail.com>
>
> Signed-off-by: Menno <mrdeg...@gmail.com>
> ---
> doc/encoders.texi | 5 +++++
> libavcodec/libopusenc.c | 14 ++++++++++++++
> 2 files changed, 19 insertions(+)
>
> diff --git a/doc/encoders.texi b/doc/encoders.texi
> index 6a410a8cb6..5cd8b1a064 100644
> --- a/doc/encoders.texi
> +++ b/doc/encoders.texi
> @@ -981,6 +981,11 @@ Other values include 0 for mono and stereo, 1 for
> surround sound with masking
> and LFE bandwidth optimizations, and 255 for independent streams with an
> unspecified channel layout.
>
> +@item disable_phase_inversion (N.A.) (requires libopus >= 1.2)
> +If set to 1, disables the use of phase inversion for intensity stereo,
> +improving the quality of mono downmixes, but slightly reducing normal stereo
> +quality. The default is 0 (phase inversion enabled).
Maybe be a bit more drastic. IMO it more than "improves the quality" of
mono, but brings it from completely unlistenable to listenable.
- Derek
> +
> @end table
>
> @anchor{libshine}
> diff --git a/libavcodec/libopusenc.c b/libavcodec/libopusenc.c
> index b449497d15..3ad10502fc 100644
> --- a/libavcodec/libopusenc.c
> +++ b/libavcodec/libopusenc.c
> @@ -39,6 +39,9 @@ typedef struct LibopusEncOpts {
> int packet_size;
> int max_bandwidth;
> int mapping_family;
> +#ifdef OPUS_SET_PHASE_INVERSION_DISABLED_REQUEST
> + int disable_phase_inversion;
> +#endif
> } LibopusEncOpts;
>
> typedef struct LibopusEncContext {
> @@ -154,6 +157,14 @@ static int libopus_configure_encoder(AVCodecContext
> *avctx, OpusMSEncoder *enc,
> "Unable to set maximum bandwidth: %s\n",
> opus_strerror(ret));
> }
>
> +#ifdef OPUS_SET_PHASE_INVERSION_DISABLED_REQUEST
> + ret = opus_multistream_encoder_ctl(enc,
> +
> OPUS_SET_PHASE_INVERSION_DISABLED(opts->disable_phase_inversion));
> + if (ret != OPUS_OK)
> + av_log(avctx, AV_LOG_WARNING,
> + "Unable to disable phase inversion: %s\n",
> + opus_strerror(ret));
> +#endif
> return OPUS_OK;
> }
>
> @@ -530,6 +541,9 @@ static const AVOption libopus_options[] = {
> { "on", "Use variable bit rate", 0, AV_OPT_TYPE_CONST, {
> .i64 = 1 }, 0, 0, FLAGS, "vbr" },
> { "constrained", "Use constrained VBR", 0, AV_OPT_TYPE_CONST, {
> .i64 = 2 }, 0, 0, FLAGS, "vbr" },
> { "mapping_family", "Channel Mapping Family",
> OFFSET(mapping_family), AV_OPT_TYPE_INT, { .i64 = -1 }, -1, 255, FLAGS,
> "mapping_family" },
> +#ifdef OPUS_SET_PHASE_INVERSION_DISABLED_REQUEST
> + { "disable_phase_inversion", "Disable phase inversion",
> OFFSET(disable_phase_inversion), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1,
> FLAGS },
> +#endif
> { NULL },
> };
>
>
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