A few optimisations.
authorCarl Hetherington <cth@carlh.net>
Sun, 3 Sep 2017 19:32:29 +0000 (20:32 +0100)
committerCarl Hetherington <cth@carlh.net>
Sun, 3 Sep 2017 19:32:29 +0000 (20:32 +0100)
src/lib/ffmpeg_decoder.cc

index 3cbd030..5e2cb86 100644 (file)
@@ -205,8 +205,10 @@ FFmpegDecoder::deinterleave_audio (shared_ptr<FFmpegAudioStream> stream) const
           of the block that do not form a complete sample or frame they will be dropped.
        */
        int const total_samples = size / bytes_per_audio_sample (stream);
-       int const frames = total_samples / stream->channels();
-       shared_ptr<AudioBuffers> audio (new AudioBuffers (stream->channels(), frames));
+       int const channels = stream->channels();
+       int const frames = total_samples / channels;
+       shared_ptr<AudioBuffers> audio (new AudioBuffers (channels, frames));
+       float** data = audio->data();
 
        switch (audio_sample_format (stream)) {
        case AV_SAMPLE_FMT_U8:
@@ -215,10 +217,10 @@ FFmpegDecoder::deinterleave_audio (shared_ptr<FFmpegAudioStream> stream) const
                int sample = 0;
                int channel = 0;
                for (int i = 0; i < total_samples; ++i) {
-                       audio->data(channel)[sample] = float(*p++) / (1 << 23);
+                       data[channel][sample] = float(*p++) / (1 << 23);
 
                        ++channel;
-                       if (channel == stream->channels()) {
+                       if (channel == channels) {
                                channel = 0;
                                ++sample;
                        }
@@ -232,10 +234,10 @@ FFmpegDecoder::deinterleave_audio (shared_ptr<FFmpegAudioStream> stream) const
                int sample = 0;
                int channel = 0;
                for (int i = 0; i < total_samples; ++i) {
-                       audio->data(channel)[sample] = float(*p++) / (1 << 15);
+                       data[channel][sample] = float(*p++) / (1 << 15);
 
                        ++channel;
-                       if (channel == stream->channels()) {
+                       if (channel == channels) {
                                channel = 0;
                                ++sample;
                        }
@@ -246,9 +248,9 @@ FFmpegDecoder::deinterleave_audio (shared_ptr<FFmpegAudioStream> stream) const
        case AV_SAMPLE_FMT_S16P:
        {
                int16_t** p = reinterpret_cast<int16_t **> (_frame->data);
-               for (int i = 0; i < stream->channels(); ++i) {
+               for (int i = 0; i < channels; ++i) {
                        for (int j = 0; j < frames; ++j) {
-                               audio->data(i)[j] = static_cast<float>(p[i][j]) / (1 << 15);
+                               data[i][j] = static_cast<float>(p[i][j]) / (1 << 15);
                        }
                }
        }
@@ -260,10 +262,10 @@ FFmpegDecoder::deinterleave_audio (shared_ptr<FFmpegAudioStream> stream) const
                int sample = 0;
                int channel = 0;
                for (int i = 0; i < total_samples; ++i) {
-                       audio->data(channel)[sample] = static_cast<float>(*p++) / 2147483648;
+                       data[channel][sample] = static_cast<float>(*p++) / 2147483648;
 
                        ++channel;
-                       if (channel == stream->channels()) {
+                       if (channel == channels) {
                                channel = 0;
                                ++sample;
                        }
@@ -274,9 +276,9 @@ FFmpegDecoder::deinterleave_audio (shared_ptr<FFmpegAudioStream> stream) const
        case AV_SAMPLE_FMT_S32P:
        {
                int32_t** p = reinterpret_cast<int32_t **> (_frame->data);
-               for (int i = 0; i < stream->channels(); ++i) {
+               for (int i = 0; i < channels; ++i) {
                        for (int j = 0; j < frames; ++j) {
-                               audio->data(i)[j] = static_cast<float>(p[i][j]) / 2147483648;
+                               data[i][j] = static_cast<float>(p[i][j]) / 2147483648;
                        }
                }
        }
@@ -288,10 +290,10 @@ FFmpegDecoder::deinterleave_audio (shared_ptr<FFmpegAudioStream> stream) const
                int sample = 0;
                int channel = 0;
                for (int i = 0; i < total_samples; ++i) {
-                       audio->data(channel)[sample] = *p++;
+                       data[channel][sample] = *p++;
 
                        ++channel;
-                       if (channel == stream->channels()) {
+                       if (channel == channels) {
                                channel = 0;
                                ++sample;
                        }
@@ -304,9 +306,9 @@ FFmpegDecoder::deinterleave_audio (shared_ptr<FFmpegAudioStream> stream) const
                float** p = reinterpret_cast<float**> (_frame->data);
                /* Sometimes there aren't as many channels in the _frame as in the stream */
                for (int i = 0; i < _frame->channels; ++i) {
-                       memcpy (audio->data(i), p[i], frames * sizeof(float));
+                       memcpy (data[i], p[i], frames * sizeof(float));
                }
-               for (int i = _frame->channels; i < stream->channels(); ++i) {
+               for (int i = _frame->channels; i < channels; ++i) {
                        audio->make_silent (i);
                }
        }