support fact chunk for wav encoder

include/libnyquist/RiffUtils.h

@@ -77,7 +77,7 @@ auto chunk = GenerateChunkCode(a, b, c, d);
 
 ChunkHeaderInfo ScanForChunk(const std::vector<uint8_t> & fileData, uint32_t chunkMarker);
     
-WaveChunkHeader MakeWaveHeader(const EncoderParams param);
+WaveChunkHeader MakeWaveHeader(const EncoderParams param, const int sampleRate);
 
 } // end namespace nqr
 

src/RiffUtils.cpp

@@ -49,7 +49,7 @@ ChunkHeaderInfo nqr::ScanForChunk(const std::vector<uint8_t> & fileData, uint32_
 
 
 
-WaveChunkHeader nqr::MakeWaveHeader(const EncoderParams param)
+WaveChunkHeader nqr::MakeWaveHeader(const EncoderParams param, const int sampleRate)
 {
     WaveChunkHeader header;
     
@@ -59,8 +59,8 @@ WaveChunkHeader nqr::MakeWaveHeader(const EncoderParams param)
     header.chunk_size = 16;
     header.format = (param.targetFormat <= PCMFormat::PCM_32) ? WaveFormatCode::FORMAT_PCM : WaveFormatCode::FORMAT_IEEE;
     header.channel_count = param.channelCount;
-    header.sample_rate = param.sampleRate;
-    header.data_rate = param.sampleRate * param.channelCount * (bitdepth / 8);
+    header.sample_rate = sampleRate;
+    header.data_rate = sampleRate * param.channelCount * (bitdepth / 8);
     header.frame_size = param.channelCount * (bitdepth/ 8);
     header.bit_depth = bitdepth;
     

src/WavEncoder.cpp

@@ -67,12 +67,6 @@ int WavEncoder::WriteFile(const EncoderParams p, const AudioData * d, const std:
         return EncoderError::BufferTooBig;
     }
     
-    // No resampling
-    if (d->sampleRate != p.sampleRate)
-    {
-        return EncoderError::UnsupportedSamplerate;
-    }
-    
     // Don't support PCM_64 or PCM_DBL
     if (GetFormatBitsPerSample(p.targetFormat) > 32)
     {
@@ -98,15 +92,20 @@ int WavEncoder::WriteFile(const EncoderParams p, const AudioData * d, const std:
     fout.write(GenerateChunkCodeChar('W', 'A', 'V', 'E'), 4);
     
     // Fmt header
-    auto header = MakeWaveHeader(p);
+    auto header = MakeWaveHeader(p, d->sampleRate);
     fout.write(reinterpret_cast<char*>(&header), sizeof(WaveChunkHeader));
     
     auto sourceBits = GetFormatBitsPerSample(d->sourceFormat);
     auto targetBits = GetFormatBitsPerSample(p.targetFormat);
     
-    if (p.targetFormat == PCM_FLT || p.targetFormat == PCM_DBL)
+    // Write out fact chunk
+    if (p.targetFormat == PCM_FLT)
     {
-        
+        uint32_t four = 4;
+        uint32_t dataSz = int(d->samples.size() / d->channelCount);
+        fout.write(GenerateChunkCodeChar('f', 'a', 'c', 't'), 4);
+        fout.write(reinterpret_cast<const char *>(&four), sizeof(four));
+        fout.write(reinterpret_cast<const char *>(&dataSz), sizeof(dataSz)); // Number of samples (per channel)
     }
     
     // Data header