cpp/openttd-patchpack/source Changeset - r12679:1015c7a9aebf

Changeset - r12679:1015c7a9aebf

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rubidium - 15 years ago 2009-08-10 17:46:44
rubidium@openttd.org

(svn r17146) -Codechange: improve the sample rate conversion a bit

2 files changed with 24 insertions and 5 deletions:

src/mixer.cpp

src/sound.cpp

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src/mixer.cpp

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@@ @@ -33,12 +33,25 @@ static uint32 _play_rate = 11025; @@
  * samples should not exceed this limit as it will sound too loud. It also
  * stops overflowing when too many sounds are played at the same time, which
  * causes an even worse sound quality.
  */
 static const int MAX_VOLUME = 128 * 128;
 /**
  * Perform the rate conversion between the input and output.
  * @param b the buffer to read the data from
  * @param frac_pos the position from the begin of the buffer till the next element
  * @tparam T the size of the buffer (8 or 16 bits)
  * @return the converted value.
  */
 template <typename T>
 static int RateConversion(T *b, int frac_pos)
+{
 	return ((b[0] * ((1 << 16) - frac_pos)) + (b[1] * frac_pos)) >> 16;
+}
 static void mix_int16(MixerChannel *sc, int16 *buffer, uint samples)
+{
 	int16 *b;
 	uint32 frac_pos;
 	uint32 frac_speed;
 	int volume_left;
@@ @@ -61,14 +74,15 @@ static void mix_int16(MixerChannel *sc, @@
 			buffer[1] = Clamp(buffer[1] + (*b * volume_right >> 16), -MAX_VOLUME, MAX_VOLUME);
 			b++;
 			buffer += 2;
 		} while (--samples > 0);
 	} else {
 		do {
 			buffer[0] = Clamp(buffer[0] + (*b * volume_left  >> 16), -MAX_VOLUME, MAX_VOLUME);
 			buffer[1] = Clamp(buffer[1] + (*b * volume_right >> 16), -MAX_VOLUME, MAX_VOLUME);
 			int data = RateConversion(b, frac_pos);
 			buffer[0] = Clamp(buffer[0] + (data * volume_left  >> 16), -MAX_VOLUME, MAX_VOLUME);
 			buffer[1] = Clamp(buffer[1] + (data * volume_right >> 16), -MAX_VOLUME, MAX_VOLUME);
 			buffer += 2;
 			frac_pos += frac_speed;
 			b += frac_pos >> 16;
 			frac_pos &= 0xffff;
 		} while (--samples > 0);
+	}
@@ @@ -102,14 +116,15 @@ static void mix_int8_to_int16(MixerChann @@
 			buffer[1] = Clamp(buffer[1] + (*b * volume_right >> 8), -MAX_VOLUME, MAX_VOLUME);
 			b++;
 			buffer += 2;
 		} while (--samples > 0);
 	} else {
 		do {
 			buffer[0] = Clamp(buffer[0] + (*b * volume_left  >> 8), -MAX_VOLUME, MAX_VOLUME);
 			buffer[1] = Clamp(buffer[1] + (*b * volume_right >> 8), -MAX_VOLUME, MAX_VOLUME);
 			int data = RateConversion(b, frac_pos);
 			buffer[0] = Clamp(buffer[0] + (data * volume_left  >> 8), -MAX_VOLUME, MAX_VOLUME);
 			buffer[1] = Clamp(buffer[1] + (data * volume_right >> 8), -MAX_VOLUME, MAX_VOLUME);
 			buffer += 2;
 			frac_pos += frac_speed;
 			b += frac_pos >> 16;
 			frac_pos &= 0xffff;
 		} while (--samples > 0);
+	}

src/sound.cpp

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@@ @@ -106,13 +106,17 @@ static void OpenBankFile(const char *fil @@
 static bool SetBankSource(MixerChannel *mc, const SoundEntry *sound)
+{
 	assert(sound != NULL);
 	if (sound->file_size == 0) return false;
 	int8 *mem = MallocT<int8>(sound->file_size);
 	int8 *mem = MallocT<int8>(sound->file_size + 2);
 	/* Add two extra bytes so rate conversion can read these
 	 * without reading out of it's input buffer. */
 	mem[sound->file_size    ] = 0;
 	mem[sound->file_size + 1] = 0;
 	FioSeekToFile(sound->file_slot, sound->file_offset);
 	FioReadBlock(mem, sound->file_size);
 	/* 16-bit PCM WAV files should be signed by default */
 	if (sound->bits_per_sample == 8) {

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