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Bug 945127 - Correct the checking of input sampling rate. r=giles

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This commit is contained in:
Shelly Lin 2013-12-11 13:56:18 +08:00
parent dbec9b0bdf
commit 38439ea439
1 changed files with 13 additions and 6 deletions
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19
content/media/encoder/OpusTrackEncoder.cpp
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@ -32,6 +32,11 @@ static const int kOpusSamplingRate = 48000;
// The duration of an Opus frame, and it must be 2.5, 5, 10, 20, 40 or 60 ms.
static const int kFrameDurationMs = 20;
// The supported sampling rate of input signal (Hz),
// must be one of the following. Will resampled to 48kHz otherwise.
static const int kOpusSupportedInputSamplingRates[5] =
{8000, 12000, 16000, 24000, 48000};
namespace {
// An endian-neutral serialization of integers. Serializing T in little endian
@ -146,12 +151,14 @@ OpusTrackEncoder::Init(int aChannels, int aSamplingRate)
if (aChannels <= 0) {
return NS_ERROR_FAILURE;
}
// The granule position is required to be incremented at a rate of 48KHz, and
// it is simply calculated as |granulepos = samples * (48000/source_rate)|,
// that is, the source sampling rate must divide 48000 evenly.
// If this constraint is not satisfied, we resample the input to 48kHz.
if (!((aSamplingRate >= 8000) && (kOpusSamplingRate / aSamplingRate) *
aSamplingRate == kOpusSamplingRate)) {
// According to www.opus-codec.org, creating an opus encoder requires the
// sampling rate of source signal be one of 8000, 12000, 16000, 24000, or
// 48000. If this constraint is not satisfied, we resample the input to 48kHz.
nsTArray<int> supportedSamplingRates;
supportedSamplingRates.AppendElements(kOpusSupportedInputSamplingRates,
MOZ_ARRAY_LENGTH(kOpusSupportedInputSamplingRates));
if (!supportedSamplingRates.Contains(aSamplingRate)) {
int error;
mResampler = speex_resampler_init(mChannels,
aSamplingRate,