static int filter_frame(AVFilterLink *inlink, AVFrame *in)
{
AVFilterContext *ctx = inlink->dst;
AVFilterLink *outlink = ctx->outputs[0];
SilenceRemoveContext *s = ctx->priv;
int i, j, threshold, ret = 0;
int nbs, nb_samples_read, nb_samples_written;
double *obuf, *ibuf = (double *)in->data[0];
AVFrame *out;
nb_samples_read = nb_samples_written = 0;
switch (s->mode) {
case SILENCE_TRIM:
silence_trim:
nbs = in->nb_samples - nb_samples_read / inlink->channels;
if (!nbs)
break;
for (i = 0; i < nbs; i++) {
threshold = 0;
for (j = 0; j < inlink->channels; j++) {
threshold |= compute_rms(s, ibuf[j]) > s->start_threshold;
}
if (threshold) {
for (j = 0; j < inlink->channels; j++) {
update_rms(s, *ibuf);
s->start_holdoff[s->start_holdoff_end++] = *ibuf++;
nb_samples_read++;
}
if (s->start_holdoff_end >= s->start_duration * inlink->channels) {
if (++s->start_found_periods >= s->start_periods) {
s->mode = SILENCE_TRIM_FLUSH;
goto silence_trim_flush;
}
s->start_holdoff_offset = 0;
s->start_holdoff_end = 0;
}
} else {
s->start_holdoff_end = 0;
for (j = 0; j < inlink->channels; j++)
update_rms(s, ibuf[j]);
ibuf += inlink->channels;
nb_samples_read += inlink->channels;
}
}
break;
case SILENCE_TRIM_FLUSH:
silence_trim_flush:
nbs = s->start_holdoff_end - s->start_holdoff_offset;
nbs -= nbs % inlink->channels;
if (!nbs)
break;
out = ff_get_audio_buffer(inlink, nbs / inlink->channels);
if (!out) {
av_frame_free(&in);
return AVERROR(ENOMEM);
}
memcpy(out->data[0], &s->start_holdoff[s->start_holdoff_offset],
nbs * sizeof(double));
s->start_holdoff_offset += nbs;
ret = ff_filter_frame(outlink, out);
if (s->start_holdoff_offset == s->start_holdoff_end) {
s->start_holdoff_offset = 0;
s->start_holdoff_end = 0;
s->mode = SILENCE_COPY;
goto silence_copy;
}
break;
case SILENCE_COPY:
silence_copy:
nbs = in->nb_samples - nb_samples_read / inlink->channels;
if (!nbs)
break;
out = ff_get_audio_buffer(inlink, nbs);
if (!out) {
av_frame_free(&in);
return AVERROR(ENOMEM);
}
obuf = (double *)out->data[0];
if (s->stop_periods) {
for (i = 0; i < nbs; i++) {
threshold = 1;
for (j = 0; j < inlink->channels; j++)
threshold &= compute_rms(s, ibuf[j]) > s->stop_threshold;
if (threshold && s->stop_holdoff_end && !s->leave_silence) {
s->mode = SILENCE_COPY_FLUSH;
flush(out, outlink, &nb_samples_written, &ret);
goto silence_copy_flush;
} else if (threshold) {
for (j = 0; j < inlink->channels; j++) {
update_rms(s, *ibuf);
*obuf++ = *ibuf++;
nb_samples_read++;
nb_samples_written++;
}
} else if (!threshold) {
for (j = 0; j < inlink->channels; j++) {
update_rms(s, *ibuf);
if (s->leave_silence) {
*obuf++ = *ibuf;
nb_samples_written++;
}
s->stop_holdoff[s->stop_holdoff_end++] = *ibuf++;
nb_samples_read++;
}
if (s->stop_holdoff_end >= s->stop_duration * inlink->channels) {
if (++s->stop_found_periods >= s->stop_periods) {
s->stop_holdoff_offset = 0;
s->stop_holdoff_end = 0;
if (!s->restart) {
s->mode = SILENCE_STOP;
flush(out, outlink, &nb_samples_written, &ret);
goto silence_stop;
} else {
s->stop_found_periods = 0;
s->start_found_periods = 0;
s->start_holdoff_offset = 0;
s->start_holdoff_end = 0;
clear_rms(s);
s->mode = SILENCE_TRIM;
flush(out, outlink, &nb_samples_written, &ret);
goto silence_trim;
}
}
s->mode = SILENCE_COPY_FLUSH;
flush(out, outlink, &nb_samples_written, &ret);
goto silence_copy_flush;
}
}
}
flush(out, outlink, &nb_samples_written, &ret);
} else {
memcpy(obuf, ibuf, sizeof(double) * nbs * inlink->channels);
ret = ff_filter_frame(outlink, out);
}
break;
case SILENCE_COPY_FLUSH:
silence_copy_flush:
nbs = s->stop_holdoff_end - s->stop_holdoff_offset;
nbs -= nbs % inlink->channels;
if (!nbs)
break;
out = ff_get_audio_buffer(inlink, nbs / inlink->channels);
if (!out) {
av_frame_free(&in);
return AVERROR(ENOMEM);
}
memcpy(out->data[0], &s->stop_holdoff[s->stop_holdoff_offset],
nbs * sizeof(double));
s->stop_holdoff_offset += nbs;
ret = ff_filter_frame(outlink, out);
if (s->stop_holdoff_offset == s->stop_holdoff_end) {
s->stop_holdoff_offset = 0;
s->stop_holdoff_end = 0;
s->mode = SILENCE_COPY;
goto silence_copy;
}
break;
case SILENCE_STOP:
silence_stop:
break;
}
av_frame_free(&in);
return ret;
}
/* Return number of samples processed in isamp and osamp. */
static int sox_silence_flow(sox_effect_t * effp, const sox_sample_t *ibuf, sox_sample_t *obuf,
size_t *isamp, size_t *osamp)
{
priv_t * silence = (priv_t *) effp->priv;
int threshold;
size_t i, j;
size_t nrOfTicks, /* sometimes wide, sometimes non-wide samples */
nrOfInSamplesRead, nrOfOutSamplesWritten; /* non-wide samples */
nrOfInSamplesRead = 0;
nrOfOutSamplesWritten = 0;
switch (silence->mode)
{
case SILENCE_TRIM:
/* Reads and discards all input data until it detects a
* sample that is above the specified threshold. Turns on
* copy mode when detected.
* Need to make sure and copy input in groups of "channels" to
* prevent getting buffers out of sync.
* nrOfTicks counts wide samples here.
*/
silence_trim:
nrOfTicks = min((*isamp-nrOfInSamplesRead),
(*osamp-nrOfOutSamplesWritten)) /
effp->in_signal.channels;
for(i = 0; i < nrOfTicks; i++)
{
threshold = 0;
for (j = 0; j < effp->in_signal.channels; j++)
{
threshold |= aboveThreshold(effp,
compute_rms(effp, ibuf[j]),
silence->start_threshold,
silence->start_unit);
}
if (threshold)
{
/* Add to holdoff buffer */
for (j = 0; j < effp->in_signal.channels; j++)
{
update_rms(effp, *ibuf);
silence->start_holdoff[
silence->start_holdoff_end++] = *ibuf++;
nrOfInSamplesRead++;
}
if (silence->start_holdoff_end >=
silence->start_duration)
{
if (++silence->start_found_periods >=
silence->start_periods)
{
silence->mode = SILENCE_TRIM_FLUSH;
goto silence_trim_flush;
}
/* Trash holdoff buffer since its not
* needed. Start looking again.
*/
silence->start_holdoff_offset = 0;
silence->start_holdoff_end = 0;
}
}
else /* !above Threshold */
{
silence->start_holdoff_end = 0;
for (j = 0; j < effp->in_signal.channels; j++)
{
update_rms(effp, ibuf[j]);
}
ibuf += effp->in_signal.channels;
nrOfInSamplesRead += effp->in_signal.channels;
}
} /* for nrOfTicks */
break;
case SILENCE_TRIM_FLUSH:
/* nrOfTicks counts non-wide samples here. */
silence_trim_flush:
nrOfTicks = min((silence->start_holdoff_end -
silence->start_holdoff_offset),
(*osamp-nrOfOutSamplesWritten));
nrOfTicks -= nrOfTicks % effp->in_signal.channels;
for(i = 0; i < nrOfTicks; i++)
{
*obuf++ = silence->start_holdoff[silence->start_holdoff_offset++];
nrOfOutSamplesWritten++;
}
/* If fully drained holdoff then switch to copy mode */
if (silence->start_holdoff_offset == silence->start_holdoff_end)
{
silence->start_holdoff_offset = 0;
silence->start_holdoff_end = 0;
silence->mode = SILENCE_COPY;
goto silence_copy;
}
break;
case SILENCE_COPY:
/* Attempts to copy samples into output buffer.
*
* Case B:
* If not looking for silence to terminate copy then
* blindly copy data into output buffer.
*
* Case A:
*
* Case 1a:
* If previous silence was detect then see if input sample is
* above threshold. If found then flush out hold off buffer
* and copy over to output buffer.
*
* Case 1b:
* If no previous silence detect then see if input sample
* is above threshold. If found then copy directly
* to output buffer.
*
* Case 2:
* If not above threshold then silence is detect so
* store in hold off buffer and do not write to output
* buffer. Even though it wasn't put in output
* buffer, inform user that input was consumed.
*
* If hold off buffer is full after this then stop
* copying data and discard data in hold off buffer.
*
* Special leave_silence logic:
*
* During this mode, go ahead and copy input
* samples to output buffer instead of holdoff buffer
* Then also short ciruit any flushes that would occur
* when non-silence is detect since samples were already
* copied. This has the effect of always leaving
* holdoff[] amount of silence but deleting any
* beyond that amount.
*
* nrOfTicks counts wide samples here.
*/
silence_copy:
nrOfTicks = min((*isamp-nrOfInSamplesRead),
(*osamp-nrOfOutSamplesWritten)) /
effp->in_signal.channels;
if (silence->stop)
{
/* Case A */
for(i = 0; i < nrOfTicks; i++)
{
threshold = 1;
for (j = 0; j < effp->in_signal.channels; j++)
{
threshold &= aboveThreshold(effp,
compute_rms(effp, ibuf[j]),
silence->stop_threshold,
silence->stop_unit);
}
/* Case 1a
* If above threshold, check to see if we where holding
* off previously. If so then flush this buffer.
* We haven't incremented any pointers yet so nothing
* is lost.
*
* If user wants to leave_silence, then we
* were already copying the data and so no
* need to flush the old data. Just resume
* copying as if we were not holding off.
*/
if (threshold && silence->stop_holdoff_end
&& !silence->leave_silence)
{
silence->mode = SILENCE_COPY_FLUSH;
goto silence_copy_flush;
}
/* Case 1b */
else if (threshold)
{
/* Not holding off so copy into output buffer */
for (j = 0; j < effp->in_signal.channels; j++)
{
update_rms(effp, *ibuf);
*obuf++ = *ibuf++;
nrOfInSamplesRead++;
nrOfOutSamplesWritten++;
}
}
/* Case 2 */
else if (!threshold)
{
/* Add to holdoff buffer */
for (j = 0; j < effp->in_signal.channels; j++)
{
update_rms(effp, *ibuf);
if (silence->leave_silence) {
*obuf++ = *ibuf;
nrOfOutSamplesWritten++;
}
silence->stop_holdoff[
silence->stop_holdoff_end++] = *ibuf++;
nrOfInSamplesRead++;
}
/* Check if holdoff buffer is greater than duration
*/
if (silence->stop_holdoff_end >=
silence->stop_duration)
{
/* Increment found counter and see if this
* is the last period. If so then exit.
*/
if (++silence->stop_found_periods >=
silence->stop_periods)
{
silence->stop_holdoff_offset = 0;
silence->stop_holdoff_end = 0;
if (!silence->restart)
{
*isamp = nrOfInSamplesRead;
*osamp = nrOfOutSamplesWritten;
silence->mode = SILENCE_STOP;
/* Return SOX_EOF since no more processing */
return (SOX_EOF);
}
else
{
silence->stop_found_periods = 0;
silence->start_found_periods = 0;
silence->start_holdoff_offset = 0;
silence->start_holdoff_end = 0;
clear_rms(effp);
silence->mode = SILENCE_TRIM;
goto silence_trim;
}
}
else
{
/* Flush this buffer and start
* looking again.
*/
silence->mode = SILENCE_COPY_FLUSH;
goto silence_copy_flush;
}
break;
} /* Filled holdoff buffer */
} /* Detected silence */
} /* For # of samples */
} /* Trimming off backend */
else /* !(silence->stop) */
{
/* Case B */
memcpy(obuf, ibuf, sizeof(sox_sample_t)*nrOfTicks*
effp->in_signal.channels);
nrOfInSamplesRead += (nrOfTicks*effp->in_signal.channels);
nrOfOutSamplesWritten += (nrOfTicks*effp->in_signal.channels);
}
break;
case SILENCE_COPY_FLUSH:
/* nrOfTicks counts non-wide samples here. */
silence_copy_flush:
nrOfTicks = min((silence->stop_holdoff_end -
silence->stop_holdoff_offset),
(*osamp-nrOfOutSamplesWritten));
nrOfTicks -= nrOfTicks % effp->in_signal.channels;
for(i = 0; i < nrOfTicks; i++)
{
*obuf++ = silence->stop_holdoff[silence->stop_holdoff_offset++];
nrOfOutSamplesWritten++;
}
/* If fully drained holdoff then return to copy mode */
if (silence->stop_holdoff_offset == silence->stop_holdoff_end)
{
silence->stop_holdoff_offset = 0;
silence->stop_holdoff_end = 0;
silence->mode = SILENCE_COPY;
goto silence_copy;
}
break;
case SILENCE_STOP:
/* This code can't be reached. */
nrOfInSamplesRead = *isamp;
break;
}
*isamp = nrOfInSamplesRead;
*osamp = nrOfOutSamplesWritten;
return (SOX_SUCCESS);
}
