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215 lines
6.1 KiB
C
215 lines
6.1 KiB
C
/* GStreamer
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* Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
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* Boston, MA 02110-1301, USA.
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*/
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/**
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* SECTION:gstaudio
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* @short_description: Support library for audio elements
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*
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* This library contains some helper functions for audio elements.
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <string.h>
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#include "audio.h"
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#include "audio-enumtypes.h"
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/**
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* gst_audio_buffer_clip:
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* @buffer: (transfer full): The buffer to clip.
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* @segment: Segment in %GST_FORMAT_TIME or %GST_FORMAT_DEFAULT to which
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* the buffer should be clipped.
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* @rate: sample rate.
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* @bpf: size of one audio frame in bytes. This is the size of one sample
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* * channels.
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*
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* Clip the buffer to the given %GstSegment.
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*
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* After calling this function the caller does not own a reference to
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* @buffer anymore.
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*
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* Returns: (transfer full): %NULL if the buffer is completely outside the configured segment,
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* otherwise the clipped buffer is returned.
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*
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* If the buffer has no timestamp, it is assumed to be inside the segment and
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* is not clipped
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*/
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GstBuffer *
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gst_audio_buffer_clip (GstBuffer * buffer, GstSegment * segment, gint rate,
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gint bpf)
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{
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GstBuffer *ret;
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GstClockTime timestamp = GST_CLOCK_TIME_NONE, duration = GST_CLOCK_TIME_NONE;
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guint64 offset = GST_BUFFER_OFFSET_NONE, offset_end = GST_BUFFER_OFFSET_NONE;
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gsize trim, size, osize;
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gboolean change_duration = TRUE, change_offset = TRUE, change_offset_end =
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TRUE;
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g_return_val_if_fail (segment->format == GST_FORMAT_TIME ||
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segment->format == GST_FORMAT_DEFAULT, buffer);
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g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
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if (!GST_BUFFER_TIMESTAMP_IS_VALID (buffer))
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/* No timestamp - assume the buffer is completely in the segment */
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return buffer;
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/* Get copies of the buffer metadata to change later.
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* Calculate the missing values for the calculations,
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* they won't be changed later though. */
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trim = 0;
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osize = size = gst_buffer_get_size (buffer);
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/* no data, nothing to clip */
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if (!size)
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return buffer;
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timestamp = GST_BUFFER_TIMESTAMP (buffer);
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GST_DEBUG ("timestamp %" GST_TIME_FORMAT, GST_TIME_ARGS (timestamp));
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if (GST_BUFFER_DURATION_IS_VALID (buffer)) {
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duration = GST_BUFFER_DURATION (buffer);
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} else {
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change_duration = FALSE;
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duration = gst_util_uint64_scale (size / bpf, GST_SECOND, rate);
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}
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if (GST_BUFFER_OFFSET_IS_VALID (buffer)) {
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offset = GST_BUFFER_OFFSET (buffer);
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} else {
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change_offset = FALSE;
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offset = 0;
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}
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if (GST_BUFFER_OFFSET_END_IS_VALID (buffer)) {
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offset_end = GST_BUFFER_OFFSET_END (buffer);
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} else {
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change_offset_end = FALSE;
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offset_end = offset + size / bpf;
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}
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if (segment->format == GST_FORMAT_TIME) {
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/* Handle clipping for GST_FORMAT_TIME */
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guint64 start, stop, cstart, cstop, diff;
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start = timestamp;
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stop = timestamp + duration;
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if (gst_segment_clip (segment, GST_FORMAT_TIME,
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start, stop, &cstart, &cstop)) {
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diff = cstart - start;
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if (diff > 0) {
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timestamp = cstart;
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if (change_duration)
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duration -= diff;
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diff = gst_util_uint64_scale (diff, rate, GST_SECOND);
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if (change_offset)
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offset += diff;
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trim += diff * bpf;
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size -= diff * bpf;
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}
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diff = stop - cstop;
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if (diff > 0) {
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/* duration is always valid if stop is valid */
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duration -= diff;
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diff = gst_util_uint64_scale (diff, rate, GST_SECOND);
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if (change_offset_end)
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offset_end -= diff;
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size -= diff * bpf;
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}
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} else {
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gst_buffer_unref (buffer);
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return NULL;
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}
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} else {
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/* Handle clipping for GST_FORMAT_DEFAULT */
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guint64 start, stop, cstart, cstop, diff;
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g_return_val_if_fail (GST_BUFFER_OFFSET_IS_VALID (buffer), buffer);
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start = offset;
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stop = offset_end;
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if (gst_segment_clip (segment, GST_FORMAT_DEFAULT,
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start, stop, &cstart, &cstop)) {
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diff = cstart - start;
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if (diff > 0) {
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offset = cstart;
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timestamp = gst_util_uint64_scale (cstart, GST_SECOND, rate);
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if (change_duration)
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duration -= gst_util_uint64_scale (diff, GST_SECOND, rate);
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trim += diff * bpf;
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size -= diff * bpf;
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}
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diff = stop - cstop;
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if (diff > 0) {
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offset_end = cstop;
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if (change_duration)
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duration -= gst_util_uint64_scale (diff, GST_SECOND, rate);
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size -= diff * bpf;
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}
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} else {
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gst_buffer_unref (buffer);
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return NULL;
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}
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}
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if (trim == 0 && size == osize) {
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ret = buffer;
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if (GST_BUFFER_TIMESTAMP (ret) != timestamp) {
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ret = gst_buffer_make_writable (ret);
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GST_BUFFER_TIMESTAMP (ret) = timestamp;
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}
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if (GST_BUFFER_DURATION (ret) != duration) {
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ret = gst_buffer_make_writable (ret);
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GST_BUFFER_DURATION (ret) = duration;
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}
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} else {
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/* Get a writable buffer and apply all changes */
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GST_DEBUG ("trim %" G_GSIZE_FORMAT " size %" G_GSIZE_FORMAT, trim, size);
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ret = gst_buffer_copy_region (buffer, GST_BUFFER_COPY_ALL, trim, size);
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gst_buffer_unref (buffer);
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GST_DEBUG ("timestamp %" GST_TIME_FORMAT, GST_TIME_ARGS (timestamp));
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GST_BUFFER_TIMESTAMP (ret) = timestamp;
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if (change_duration)
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GST_BUFFER_DURATION (ret) = duration;
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if (change_offset)
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GST_BUFFER_OFFSET (ret) = offset;
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if (change_offset_end)
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GST_BUFFER_OFFSET_END (ret) = offset_end;
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}
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return ret;
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}
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