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| author | Stefano Sabatini <stefasab@gmail.com> | 2023-08-26 15:45:33 +0200 |
|---|---|---|
| committer | Stefano Sabatini <stefasab@gmail.com> | 2023-10-06 09:49:47 +0200 |
| commit | 00eb4966aa8a71a70c4758254027fdc6925f8f86 (patch) | |
| tree | 85249666723c78a3674b6883b30a9604e96a93f2 | |
| parent | 7449a00d2dc7cbbdde2a3c19869e008bf682121c (diff) | |
doc/encoders/libopus: clarify lowdelay and cutoff options
Extend descriptions for the application=lowdelay and cutoff options.
Based on notes by Mingye Wang.
Address issues:
http://trac.ffmpeg.org/ticket/10330
http://trac.ffmpeg.org/ticket/10343
| -rw-r--r-- | doc/encoders.texi | 7 | ||||
| -rw-r--r-- | libavcodec/libopusenc.c | 2 |
2 files changed, 6 insertions, 3 deletions
diff --git a/doc/encoders.texi b/doc/encoders.texi index a6fef8a8f4..8b2ab937d1 100644 --- a/doc/encoders.texi +++ b/doc/encoders.texi @@ -977,14 +977,17 @@ Favor improved speech intelligibility. @item audio Favor faithfulness to the input (the default). @item lowdelay -Restrict to only the lowest delay modes. +Restrict to only the lowest delay modes by disabling voice-optimized +modes. @end table @item cutoff (N.A.) Set cutoff bandwidth in Hz. The argument must be exactly one of the following: 4000, 6000, 8000, 12000, or 20000, corresponding to narrowband, mediumband, wideband, super wideband, and fullband -respectively. The default is 0 (cutoff disabled). +respectively. The default is 0 (cutoff disabled). Note that libopus +forces a wideband cutoff for bitrates < 15 kbps, unless CELT-only +(@option{application} set to @samp{lowdelay}) mode is used. @item mapping_family (@emph{mapping_family}) Set channel mapping family to be used by the encoder. The default value of -1 diff --git a/libavcodec/libopusenc.c b/libavcodec/libopusenc.c index 5a0786f32f..f395d84af5 100644 --- a/libavcodec/libopusenc.c +++ b/libavcodec/libopusenc.c @@ -547,7 +547,7 @@ static const AVOption libopus_options[] = { { "application", "Intended application type", OFFSET(application), AV_OPT_TYPE_INT, { .i64 = OPUS_APPLICATION_AUDIO }, OPUS_APPLICATION_VOIP, OPUS_APPLICATION_RESTRICTED_LOWDELAY, FLAGS, "application" }, { "voip", "Favor improved speech intelligibility", 0, AV_OPT_TYPE_CONST, { .i64 = OPUS_APPLICATION_VOIP }, 0, 0, FLAGS, "application" }, { "audio", "Favor faithfulness to the input", 0, AV_OPT_TYPE_CONST, { .i64 = OPUS_APPLICATION_AUDIO }, 0, 0, FLAGS, "application" }, - { "lowdelay", "Restrict to only the lowest delay modes", 0, AV_OPT_TYPE_CONST, { .i64 = OPUS_APPLICATION_RESTRICTED_LOWDELAY }, 0, 0, FLAGS, "application" }, + { "lowdelay", "Restrict to only the lowest delay modes, disable voice-optimized 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 }, |