Expose some of the settings used in the disable_standby_mode.
Specifically, firstly, the disable_standby_mode_silence_threshold, which is the amount of audio in the output device's hardware buffer. It should normally be close to the value givein in the audio_backend_buffer_desired_length_in_seconds setting. If it drops to this value, silence is added to the buffer to prevent the output device from becoming idle. Secondly, the disable_standby_mode_silence_scan_interval is the time between checks of the output device's hardware buffer. The code for generating frames of possibly-dithered silence has been simplified.
This commit is contained in:
Mike Brady
@@ -1368,61 +1368,62 @@ int64_t generate_zero_frames(char *outp, size_t number_of_frames, enum sps_forma
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// return the last random number used
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// assuming the buffer has been assigned
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// add a TPDF dither -- see
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// http://educypedia.karadimov.info/library/DitherExplained.pdf
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// and the discussion around https://www.hydrogenaud.io/forums/index.php?showtopic=16963&st=25
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// I think, for a 32 --> 16 bits, the range of
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// random numbers needs to be from -2^16 to 2^16, i.e. from -65536 to 65536 inclusive, not from
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// -32768 to +32767
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// Actually, what would be generated here is from -65535 to 65535, i.e. one less on the limits.
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// See the original paper at
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// http://www.ece.rochester.edu/courses/ECE472/resources/Papers/Lipshitz_1992.pdf
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// by Lipshitz, Wannamaker and Vanderkooy, 1992.
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int64_t dither_mask = 0;
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switch (format) {
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case SPS_FORMAT_S32:
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case SPS_FORMAT_S32_LE:
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case SPS_FORMAT_S32_BE:
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dither_mask = (int64_t)1 << (64 - 32);
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break;
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case SPS_FORMAT_S24:
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case SPS_FORMAT_S24_LE:
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case SPS_FORMAT_S24_BE:
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case SPS_FORMAT_S24_3LE:
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case SPS_FORMAT_S24_3BE:
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dither_mask = (int64_t)1 << (64 - 24);
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break;
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case SPS_FORMAT_S16:
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case SPS_FORMAT_S16_LE:
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case SPS_FORMAT_S16_BE:
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dither_mask = (int64_t)1 << (64 - 16);
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break;
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case SPS_FORMAT_S8:
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case SPS_FORMAT_U8:
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dither_mask = (int64_t)1 << (64 - 8);
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break;
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case SPS_FORMAT_UNKNOWN:
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die("Unexpected SPS_FORMAT_UNKNOWN while calculating dither mask.");
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break;
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case SPS_FORMAT_AUTO:
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die("Unexpected SPS_FORMAT_AUTO while calculating dither mask.");
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break;
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case SPS_FORMAT_INVALID:
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die("Unexpected SPS_FORMAT_INVALID while calculating dither mask.");
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break;
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}
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dither_mask -= 1;
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int64_t previous_random_number = random_number_in;
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char *p = outp;
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size_t sample_number;
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for (sample_number = 0; sample_number < number_of_frames * 2; sample_number++) {
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int64_t hyper_sample = 0;
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// add a TPDF dither -- see
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// http://educypedia.karadimov.info/library/DitherExplained.pdf
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// and the discussion around https://www.hydrogenaud.io/forums/index.php?showtopic=16963&st=25
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// I think, for a 32 --> 16 bits, the range of
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// random numbers needs to be from -2^16 to 2^16, i.e. from -65536 to 65536 inclusive, not from
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// -32768 to +32767
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// Actually, what would be generated here is from -65535 to 65535, i.e. one less on the limits.
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// See the original paper at
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// http://www.ece.rochester.edu/courses/ECE472/resources/Papers/Lipshitz_1992.pdf
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// by Lipshitz, Wannamaker and Vanderkooy, 1992.
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int64_t dither_mask = 0;
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switch (format) {
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case SPS_FORMAT_S32:
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case SPS_FORMAT_S32_LE:
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case SPS_FORMAT_S32_BE:
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dither_mask = (int64_t)1 << (64 - 32);
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break;
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case SPS_FORMAT_S24:
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case SPS_FORMAT_S24_LE:
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case SPS_FORMAT_S24_BE:
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case SPS_FORMAT_S24_3LE:
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case SPS_FORMAT_S24_3BE:
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dither_mask = (int64_t)1 << (64 - 24);
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break;
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case SPS_FORMAT_S16:
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case SPS_FORMAT_S16_LE:
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case SPS_FORMAT_S16_BE:
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dither_mask = (int64_t)1 << (64 - 16);
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break;
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case SPS_FORMAT_S8:
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case SPS_FORMAT_U8:
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dither_mask = (int64_t)1 << (64 - 8);
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break;
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case SPS_FORMAT_UNKNOWN:
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die("Unexpected SPS_FORMAT_UNKNOWN while calculating dither mask.");
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break;
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case SPS_FORMAT_AUTO:
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die("Unexpected SPS_FORMAT_AUTO while calculating dither mask.");
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break;
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case SPS_FORMAT_INVALID:
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die("Unexpected SPS_FORMAT_INVALID while calculating dither mask.");
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break;
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}
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dither_mask -= 1;
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// int64_t r = r64i();
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int64_t r = ranarray64i();
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int64_t tpdf = (r & dither_mask) - (previous_random_number & dither_mask);
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@@ -1434,126 +1435,87 @@ int64_t generate_zero_frames(char *outp, size_t number_of_frames, enum sps_forma
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// move the result to the desired position in the int64_t
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char *op = p;
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int result; // this is the length of the sample
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int sample_length; // this is the length of the sample
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uint8_t byt;
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switch (format) {
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case SPS_FORMAT_S32:
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hyper_sample >>= (64 - 32);
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*(int32_t *)op = hyper_sample;
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result = 4;
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sample_length = 4;
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break;
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case SPS_FORMAT_S32_LE:
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hyper_sample >>= (64 - 32);
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byt = (uint8_t)hyper_sample;
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*op++ = byt;
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byt = (uint8_t)(hyper_sample >> 8);
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*op++ = byt;
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byt = (uint8_t)(hyper_sample >> 16);
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*op++ = byt;
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byt = (uint8_t)(hyper_sample >> 24);
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*op++ = byt;
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result = 4;
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*op++ = (uint8_t)(hyper_sample >> (64 - 32)); // 32 bits, ls byte
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*op++ = (uint8_t)(hyper_sample >> (64 - 32 + 8)); // 32 bits, less significant middle byte
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*op++ = (uint8_t)(hyper_sample >> (64 - 32 + 16)); // 32 bits, more significant middle byte
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*op = (uint8_t)(hyper_sample >> (64 - 32 + 24)); // 32 bits, ms byte
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sample_length = 4;
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break;
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case SPS_FORMAT_S32_BE:
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hyper_sample >>= (64 - 32);
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byt = (uint8_t)(hyper_sample >> 24);
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*op++ = byt;
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byt = (uint8_t)(hyper_sample >> 16);
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*op++ = byt;
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byt = (uint8_t)(hyper_sample >> 8);
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*op++ = byt;
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byt = (uint8_t)hyper_sample;
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*op++ = byt;
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result = 4;
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*op++ = (uint8_t)(hyper_sample >> (64 - 32 + 24)); // 32 bits, ms byte
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*op++ = (uint8_t)(hyper_sample >> (64 - 32 + 16)); // 32 bits, more significant middle byte
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*op++ = (uint8_t)(hyper_sample >> (64 - 32 + 8)); // 32 bits, less significant middle byte
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*op = (uint8_t)(hyper_sample >> (64 - 32)); // 32 bits, ls byte
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sample_length = 4;
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break;
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case SPS_FORMAT_S24_3LE:
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hyper_sample >>= (64 - 24);
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byt = (uint8_t)hyper_sample;
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*op++ = byt;
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byt = (uint8_t)(hyper_sample >> 8);
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*op++ = byt;
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byt = (uint8_t)(hyper_sample >> 16);
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*op++ = byt;
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result = 3;
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*op++ = (uint8_t)(hyper_sample >> (64 - 24)); // 24 bits, ls byte
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*op++ = (uint8_t)(hyper_sample >> (64 - 24 + 8)); // 24 bits, middle byte
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*op = (uint8_t)(hyper_sample >> (64 - 24 + 16)); // 24 bits, ms byte
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sample_length = 3;
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break;
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case SPS_FORMAT_S24_3BE:
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hyper_sample >>= (64 - 24);
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byt = (uint8_t)(hyper_sample >> 16);
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*op++ = byt;
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byt = (uint8_t)(hyper_sample >> 8);
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*op++ = byt;
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byt = (uint8_t)hyper_sample;
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*op++ = byt;
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result = 3;
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*op++ = (uint8_t)(hyper_sample >> (64 - 24 + 16)); // 24 bits, ms byte
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*op++ = (uint8_t)(hyper_sample >> (64 - 24 + 8)); // 24 bits, middle byte
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*op = (uint8_t)(hyper_sample >> (64 - 24)); // 24 bits, ls byte
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sample_length = 3;
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break;
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case SPS_FORMAT_S24:
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hyper_sample >>= (64 - 24);
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*(int32_t *)op = hyper_sample;
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result = 4;
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sample_length = 4;
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break;
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case SPS_FORMAT_S24_LE:
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hyper_sample >>= (64 - 24);
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byt = (uint8_t)hyper_sample;
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*op++ = byt;
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byt = (uint8_t)(hyper_sample >> 8);
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*op++ = byt;
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byt = (uint8_t)(hyper_sample >> 16);
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*op++ = byt;
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*op++ = 0;
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result = 4;
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*op++ = (uint8_t)(hyper_sample >> (64 - 24)); // 24 bits, ls byte
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*op++ = (uint8_t)(hyper_sample >> (64 - 24 + 8)); // 24 bits, middle byte
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*op++ = (uint8_t)(hyper_sample >> (64 - 24 + 16)); // 24 bits, ms byte
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*op = 0;
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sample_length = 4;
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break;
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case SPS_FORMAT_S24_BE:
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hyper_sample >>= (64 - 24);
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*op++ = 0;
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byt = (uint8_t)(hyper_sample >> 16);
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*op++ = byt;
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byt = (uint8_t)(hyper_sample >> 8);
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*op++ = byt;
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byt = (uint8_t)hyper_sample;
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*op++ = byt;
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result = 4;
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*op++ = (uint8_t)(hyper_sample >> (64 - 24 + 16)); // 24 bits, ms byte
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*op++ = (uint8_t)(hyper_sample >> (64 - 24 + 8)); // 24 bits, middle byte
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*op = (uint8_t)(hyper_sample >> (64 - 24)); // 24 bits, ls byte
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sample_length = 4;
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break;
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case SPS_FORMAT_S16_LE:
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hyper_sample >>= (64 - 16);
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byt = (uint8_t)hyper_sample;
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*op++ = byt;
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byt = (uint8_t)(hyper_sample >> 8);
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*op++ = byt;
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result = 2;
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*op++ = (uint8_t)(hyper_sample >> (64 - 16));
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*op++ = (uint8_t)(hyper_sample >> (64 - 16 + 8)); // 16 bits, ms byte
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sample_length = 2;
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break;
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case SPS_FORMAT_S16_BE:
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hyper_sample >>= (64 - 16);
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byt = (uint8_t)(hyper_sample >> 8);
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*op++ = byt;
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byt = (uint8_t)hyper_sample;
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*op++ = byt;
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result = 2;
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*op++ = (uint8_t)(hyper_sample >> (64 - 16 + 8)); // 16 bits, ms byte
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*op = (uint8_t)(hyper_sample >> (64 - 16));
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sample_length = 2;
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break;
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case SPS_FORMAT_S16:
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hyper_sample >>= (64 - 16);
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*(int16_t *)op = (int16_t)hyper_sample;
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result = 2;
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*(int16_t *)op = (int16_t)(hyper_sample >> (64 - 16));
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sample_length = 2;
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break;
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case SPS_FORMAT_S8:
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hyper_sample >>= (int8_t)(64 - 8);
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*op = hyper_sample;
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result = 1;
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*op = (int8_t)(hyper_sample >> (64 - 8));
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sample_length = 1;
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break;
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case SPS_FORMAT_U8:
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hyper_sample >>= (uint8_t)(64 - 8);
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hyper_sample += 128;
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*op = hyper_sample;
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result = 1;
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*op = 128 + (uint8_t)(hyper_sample >> (64 - 8));
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sample_length = 1;
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break;
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default:
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result = 0; // stop a compiler warning
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sample_length = 0; // stop a compiler warning
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die("Unexpected SPS_FORMAT_* with index %d while outputting silence", format);
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}
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p += result;
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p += sample_length;
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previous_random_number = r;
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}
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// hack
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// memset(outp,0,number_of_frames * 4);
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return previous_random_number;
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}
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