[FFmpeg-devel] [PATCH] avcodec/libopusenc: add option to set inband FEC

[Gyan Doshi]

Plan to push in a day.

On 06-09-2020 12:27 pm, Gyan Doshi wrote:
> ---
>   doc/encoders.texi       | 5 +++++
>   libavcodec/libopusenc.c | 9 +++++++++
>   2 files changed, 14 insertions(+)
>
> diff --git a/doc/encoders.texi b/doc/encoders.texi
> index 69bf742c2d..a48b15eb1b 100644
> --- a/doc/encoders.texi
> +++ b/doc/encoders.texi
> @@ -953,6 +953,11 @@ The default is 20ms.
>   @item packet_loss (@emph{expect-loss})
>   Set expected packet loss percentage. The default is 0.
>   
> + at item fec (@emph{n/a})
> +Enable inband forward error correction. @option{packet_loss} must be non-zero
> +to take advantage - frequency of FEC 'side-data' is proportional to expected packet loss.
> +Default is disabled.
> +
>   @item application (N.A.)
>   Set intended application type. Valid options are listed below:
>   
> diff --git a/libavcodec/libopusenc.c b/libavcodec/libopusenc.c
> index 13017ac323..bf2d04b4fb 100644
> --- a/libavcodec/libopusenc.c
> +++ b/libavcodec/libopusenc.c
> @@ -34,6 +34,7 @@ typedef struct LibopusEncOpts {
>       int vbr;
>       int application;
>       int packet_loss;
> +    int fec;
>       int complexity;
>       float frame_duration;
>       int packet_size;
> @@ -149,6 +150,13 @@ static int libopus_configure_encoder(AVCodecContext *avctx, OpusMSEncoder *enc,
>                  "Unable to set expected packet loss percentage: %s\n",
>                  opus_strerror(ret));
>   
> +    ret = opus_multistream_encoder_ctl(enc,
> +                                       OPUS_SET_INBAND_FEC(opts->fec));
> +    if (ret != OPUS_OK)
> +        av_log(avctx, AV_LOG_WARNING,
> +               "Unable to set inband FEC: %s\n",
> +               opus_strerror(ret));
> +
>       if (avctx->cutoff) {
>           ret = opus_multistream_encoder_ctl(enc,
>                                              OPUS_SET_MAX_BANDWIDTH(opts->max_bandwidth));
> @@ -544,6 +552,7 @@ static const AVOption libopus_options[] = {
>           { "lowdelay",       "Restrict to only the lowest delay modes", 0, AV_OPT_TYPE_CONST, { .i64 = OPUS_APPLICATION_RESTRICTED_LOWDELAY }, 0, 0, FLAGS, "application" },
>       { "frame_duration", "Duration of a frame in milliseconds", OFFSET(frame_duration), AV_OPT_TYPE_FLOAT, { .dbl = 20.0 }, 2.5, 120.0, FLAGS },
>       { "packet_loss",    "Expected packet loss percentage",     OFFSET(packet_loss),    AV_OPT_TYPE_INT,   { .i64 = 0 },    0,   100,  FLAGS },
> +    { "fec",             "Enable inband FEC. Expected packet loss must be non-zero",     OFFSET(fec),    AV_OPT_TYPE_BOOL,   { .i64 = 0 }, 0, 1, FLAGS },
>       { "vbr",            "Variable bit rate mode",              OFFSET(vbr),            AV_OPT_TYPE_INT,   { .i64 = 1 },    0,   2,    FLAGS, "vbr" },
>           { "off",            "Use constant bit rate", 0, AV_OPT_TYPE_CONST, { .i64 = 0 }, 0, 0, FLAGS, "vbr" },
>           { "on",             "Use variable bit rate", 0, AV_OPT_TYPE_CONST, { .i64 = 1 }, 0, 0, FLAGS, "vbr" },