Correcting the ACM upmixing from mono/stereo to surround
This CL corrects the upmixing from mono/stereo to surround in the audio
coding module.
Bug: webrtc:11083
Change-Id: Ic529107d59ff54a8e48b0424cbdf2b49b7a65c12
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/159705
Commit-Queue: Per Åhgren <peah@webrtc.org>
Reviewed-by: Sam Zackrisson <saza@webrtc.org>
Reviewed-by: Henrik Lundin <henrik.lundin@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29792}
diff --git a/modules/audio_coding/acm2/audio_coding_module.cc b/modules/audio_coding/acm2/audio_coding_module.cc
index 314afd7..0232f27 100644
--- a/modules/audio_coding/acm2/audio_coding_module.cc
+++ b/modules/audio_coding/acm2/audio_coding_module.cc
@@ -246,18 +246,22 @@
size_t in_index = 0;
size_t out_index = 0;
- // When upmixing is needed, duplicate the last channel of the input.
+ // When upmixing is needed, copy the available channels directly, and set the
+ // remaining channels to zero.
if (input.num_channels_ < num_output_channels) {
for (size_t k = 0; k < input.samples_per_channel_; ++k) {
for (size_t j = 0; j < input.num_channels_; ++j) {
(*output)[out_index++] = input_data[in_index++];
}
- RTC_DCHECK_GT(in_index, 0);
- const int16_t value_last_channel = input_data[in_index - 1];
for (size_t j = input.num_channels_; j < num_output_channels; ++j) {
- (*output)[out_index++] = value_last_channel;
+ (*output)[out_index++] = 0;
}
+ RTC_DCHECK_EQ(in_index, (k + 1) * input.num_channels_);
+ RTC_DCHECK_EQ(out_index, (k + 1) * num_output_channels);
}
+ RTC_DCHECK_EQ(in_index, input.samples_per_channel_ * input.num_channels_);
+ RTC_DCHECK_EQ(out_index, input.samples_per_channel_ * num_output_channels);
+
return;
}