[Libav-user] Audio silence detector avfilter

[Сергей Икол]

Thank you so much.
Yes it solved my problem

пн, 30 лист. 2020 о 12:38 Paul B Mahol <onemda at gmail.com> пише:

>
>
> On Mon, Nov 30, 2020 at 11:04 AM Сергей Икол <sergbest0 at gmail.com> wrote:
>
>> Hello everybody!
>> I need help solving my problem.
>>
>> I wanted to make a C++ implementation of the Audio silence detector. I
>> used the example from github (
>> https://github.com/FFmpeg/FFmpeg/blob/master/libavfilter/af_silencedetect.c).
>> I have also simplified this example to the following form.
>> const int nb_samples = this->frame->nb_samples * nb_channels;
>>
>
> This code reads out of bounds, because nb_samples for planar sample format
> you use below is wrongly calculated.
>
> Note difference between planar and packed sample formats.
>
>
>
>> const int64_t nb_samples_notify = this->srate * silence->duration *
>> this->nb_channels:
>> if (this->frame->format == AV_SAMPLE_FMT_S16P) {
>>
>> const int16_t *p = (const int16_t *)this->frame->data[0];
>>
>>
>> for (int i = 0; i < nb_samples; i++, p++) {
>>
>> if (*p < this->silence->noise && *p > -silence->noise) {
>>
>> if (!this->silence->start) {
>>
>> this->silence->nb_null_samples++;
>>
>> if (this->silence->nb_null_samples >= nb_samples_notify) {
>> //nb_samples_notify
>>
>> this->silence->start = this->frame->pts - (int64_t)(this->silence->
>> duration / av_q2d(time_base) + .5);
>>
>>
>> Log::write("silence detected start = " + std::to_string(this->
>> getCurrentSec()));
>>
>> }
>>
>> }
>>
>> } else {
>>
>> if (this->silence->start) {
>>
>> this->silent = false;
>>
>> Log::write("silence detected end = " + std::to_string(this->getCurrentSec
>> ()));
>>
>> }
>>
>> this->silence->nb_null_samples = this->silence->start = 0;
>>
>> }
>>
>> }
>>
>> }
>>
>> nb_samples = 2304
>> srate = 48000
>> nb_chaneks = 2
>> noise = 0.001
>> duratiion = 0.7
>> //
>> input video file format - * .ts
>> audio codec - mp2
>>
>> In "*p" I get very strange data (for example -22634) and as a result,
>> silence was not detected.
>>
>> Please tell me what I'm doing wrong? (because ffmpeg can find silence in
>> this file)
>>
>> _______________________________________________
>> Libav-user mailing list
>> Libav-user at ffmpeg.org
>> https://ffmpeg.org/mailman/listinfo/libav-user
>>
>> To unsubscribe, visit link above, or email
>> libav-user-request at ffmpeg.org with subject "unsubscribe".
>
> _______________________________________________
> Libav-user mailing list
> Libav-user at ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/libav-user
>
> To unsubscribe, visit link above, or email
> libav-user-request at ffmpeg.org with subject "unsubscribe".
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://ffmpeg.org/pipermail/libav-user/attachments/20201130/8cbd89b7/attachment.html>