| Message ID | 20190930133647.6290-2-lance.lmwang@gmail.com |
|---|---|
| State | Superseded |
| Headers | show |
On Mon, Sep 30, 2019 at 21:36:43 +0800, lance.lmwang@gmail.com wrote: > -The printed times and duration are expressed in seconds. > +The printed times and duration are expressed in seconds. The @code{lavfi.silence_start} > +or @code{lavfi.silence_start.X} metadata key is set on the first frame whose timestamp > +equals or exceeds the detection duration and it contains the timestamp of the first > +frame of the silence. > + > +The @code{lavfi.silence_duration} or @code{lavfi.silence_duration.X} and > +@code{lavfi.silence_end} or @code{lavfi.silence_end.X}metadata keys are set on the > +first frame after the silence. Where @code{X} is the channel number and .X is used > +if @option{mono} is enabled. I don't understand. Literal ".X" (which you should write as "@code{.X}", by the way)? And if not mono, it's ".0", ".1"? And when is ".N" completely omitted? This is a bit unclear to me, without experimenting or looking at the code. Cheers, Moritz
On Tue, Oct 01, 2019 at 09:40:45AM +0200, Moritz Barsnick wrote: > On Mon, Sep 30, 2019 at 21:36:43 +0800, lance.lmwang@gmail.com wrote: > > -The printed times and duration are expressed in seconds. > > +The printed times and duration are expressed in seconds. The @code{lavfi.silence_start} > > +or @code{lavfi.silence_start.X} metadata key is set on the first frame whose timestamp > > +equals or exceeds the detection duration and it contains the timestamp of the first > > +frame of the silence. > > + > > +The @code{lavfi.silence_duration} or @code{lavfi.silence_duration.X} and > > +@code{lavfi.silence_end} or @code{lavfi.silence_end.X}metadata keys are set on the > > +first frame after the silence. Where @code{X} is the channel number and .X is used > > +if @option{mono} is enabled. > > I don't understand. Literal ".X" (which you should write as > "@code{.X}", by the way)? And if not mono, it's ".0", ".1"? And when is > ".N" completely omitted? By the code, if it's mono mode, it'll output lavfi.silence_duration metadata, if not mono, it'll output lavfi.silence_duration.0, lavfi.silence_duration.1(0, 1 is the channel number). Please advise how to describe this clearly. > > This is a bit unclear to me, without experimenting or looking at the > code. > > Cheers, > Moritz > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
On Mon, Oct 07, 2019 at 22:23:21 +0800, Limin Wang wrote: > On Tue, Oct 01, 2019 at 09:40:45AM +0200, Moritz Barsnick wrote: > > On Mon, Sep 30, 2019 at 21:36:43 +0800, lance.lmwang@gmail.com wrote: > > > -The printed times and duration are expressed in seconds. > > > +The printed times and duration are expressed in seconds. The @code{lavfi.silence_start} > > > +or @code{lavfi.silence_start.X} metadata key is set on the first frame whose timestamp > > > +equals or exceeds the detection duration and it contains the timestamp of the first > > > +frame of the silence. > > > + > > > +The @code{lavfi.silence_duration} or @code{lavfi.silence_duration.X} and > > > +@code{lavfi.silence_end} or @code{lavfi.silence_end.X}metadata keys are set on the > > > +first frame after the silence. Where @code{X} is the channel number and .X is used > > > +if @option{mono} is enabled. > > > > I don't understand. Literal ".X" (which you should write as > > "@code{.X}", by the way)? And if not mono, it's ".0", ".1"? And when is > > ".N" completely omitted? > By the code, if it's mono mode, it'll output lavfi.silence_duration metadata, if not mono, > it'll output lavfi.silence_duration.0, lavfi.silence_duration.1(0, 1 is the channel number). > Please advise how to describe this clearly. Well, I must say I was confused by the option "mono", because it does the opposite in my opinion[*]. Anyway, since it's technically correct, I would rearrange or explain as such: The @code{lavfi.silence_duration} or @code{lavfi.silence_duration.X} and @code{lavfi.silence_end} or @code{lavfi.silence_end.X} metadata keys are set on the first frame after the silence. If @option{mono} is enabled, and each channel is evaluated separately, the @code{.X} suffixed keys are used, and @code{X} corresponds to the channel number. [*] In "mono" mode, from its name, I would have expected all the channels to be mixed down and interpreted as a monaural signal. But this is actually what happens if "mono" mode is *not* selected, apparently. In reality, in "mono" mode, each channel is interpreted separately, but that doesn't make these mono, in my opinion. But there's nothing we can change about that now. ;-) Cheers, Moritz
On Tue, Oct 08, 2019 at 02:21:06PM +0200, Moritz Barsnick wrote: > On Mon, Oct 07, 2019 at 22:23:21 +0800, Limin Wang wrote: > > On Tue, Oct 01, 2019 at 09:40:45AM +0200, Moritz Barsnick wrote: > > > On Mon, Sep 30, 2019 at 21:36:43 +0800, lance.lmwang@gmail.com wrote: > > > > -The printed times and duration are expressed in seconds. > > > > +The printed times and duration are expressed in seconds. The @code{lavfi.silence_start} > > > > +or @code{lavfi.silence_start.X} metadata key is set on the first frame whose timestamp > > > > +equals or exceeds the detection duration and it contains the timestamp of the first > > > > +frame of the silence. > > > > + > > > > +The @code{lavfi.silence_duration} or @code{lavfi.silence_duration.X} and > > > > +@code{lavfi.silence_end} or @code{lavfi.silence_end.X}metadata keys are set on the > > > > +first frame after the silence. Where @code{X} is the channel number and .X is used > > > > +if @option{mono} is enabled. > > > > > > I don't understand. Literal ".X" (which you should write as > > > "@code{.X}", by the way)? And if not mono, it's ".0", ".1"? And when is > > > ".N" completely omitted? > > By the code, if it's mono mode, it'll output lavfi.silence_duration metadata, if not mono, > > it'll output lavfi.silence_duration.0, lavfi.silence_duration.1(0, 1 is the channel number). > > Please advise how to describe this clearly. > > Well, I must say I was confused by the option "mono", because it does > the opposite in my opinion[*]. > > Anyway, since it's technically correct, I would rearrange or explain as > such: > > The @code{lavfi.silence_duration} or @code{lavfi.silence_duration.X} > and @code{lavfi.silence_end} or @code{lavfi.silence_end.X} metadata > keys are set on the first frame after the silence. If @option{mono} is > enabled, and each channel is evaluated separately, the @code{.X} > suffixed keys are used, and @code{X} corresponds to the channel number. OK, I'll update it by your description, it's more native to understand. > > [*] In "mono" mode, from its name, I would have expected all the > channels to be mixed down and interpreted as a monaural signal. But > this is actually what happens if "mono" mode is *not* selected, > apparently. In reality, in "mono" mode, each channel is interpreted > separately, but that doesn't make these mono, in my opinion. But > there's nothing we can change about that now. ;-) Yes, the mono mode make the metadata difficult to process also. > > Cheers, > Moritz > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
diff --git a/doc/filters.texi b/doc/filters.texi index 333f502..697ec21 100644 --- a/doc/filters.texi +++ b/doc/filters.texi @@ -4563,7 +4563,15 @@ This filter logs a message when it detects that the input audio volume is less or equal to a noise tolerance value for a duration greater or equal to the minimum detected noise duration. -The printed times and duration are expressed in seconds. +The printed times and duration are expressed in seconds. The @code{lavfi.silence_start} +or @code{lavfi.silence_start.X} metadata key is set on the first frame whose timestamp +equals or exceeds the detection duration and it contains the timestamp of the first +frame of the silence. + +The @code{lavfi.silence_duration} or @code{lavfi.silence_duration.X} and +@code{lavfi.silence_end} or @code{lavfi.silence_end.X}metadata keys are set on the +first frame after the silence. Where @code{X} is the channel number and .X is used +if @option{mono} is enabled. The filter accepts the following options: diff --git a/libavfilter/af_silencedetect.c b/libavfilter/af_silencedetect.c index c31109f..193d0fe 100644 --- a/libavfilter/af_silencedetect.c +++ b/libavfilter/af_silencedetect.c @@ -187,7 +187,6 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *insamples) s->frame_end = insamples->pts + av_rescale_q(insamples->nb_samples, (AVRational){ 1, s->last_sample_rate }, inlink->time_base); - // TODO: document metadata s->silencedetect(s, insamples, nb_samples, nb_samples_notify, inlink->time_base);