diff options
| -rw-r--r-- | src/odr-audioenc.cpp | 53 |
1 files changed, 47 insertions, 6 deletions
diff --git a/src/odr-audioenc.cpp b/src/odr-audioenc.cpp index b009b37..b960633 100644 --- a/src/odr-audioenc.cpp +++ b/src/odr-audioenc.cpp @@ -1,6 +1,6 @@ /* ------------------------------------------------------------------ * Copyright (C) 2011 Martin Storsjo - * Copyright (C) 2016 Matthias P. Braendli + * Copyright (C) 2017 Matthias P. Braendli * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -88,7 +88,7 @@ extern "C" { #include "libtoolame-dab/toolame.h" } - +using vec_u8 = std::vector<uint8_t>; //! Enumeration of encoders we can use enum class encoder_selection_t { @@ -297,10 +297,49 @@ int prepare_aac_encoder( chrono::steady_clock::time_point timepoint_last_compensation; +/*! Do drift compensation by distributing the missing samples over + * the whole input buffer instead of having a bunch of missing samples + * at the end only. + * + * This expands (in time) the received samples over the whole duration + * of the buffer. + */ +static void expand_missing_samples(vec_u8& buf, int channels, size_t valid_bytes) +{ + const size_t bytes_per_sample = BYTES_PER_SAMPLE * channels; + assert(buf.size() % bytes_per_sample == 0); + assert(buf.size() > valid_bytes); + const size_t valid_samples = valid_bytes / bytes_per_sample; + const size_t missing_samples = + (buf.size() / bytes_per_sample) - valid_samples; + + // We only fix up to 10% missing samples + if (missing_samples * bytes_per_sample > buf.size() / 10) { + for (size_t i = valid_samples * bytes_per_sample; i < buf.size(); i++) { + buf[i] = 0; + } + } + + const vec_u8 source_buf(buf); + size_t source_ix = 0; + + for (size_t i = 0; i < buf.size() / bytes_per_sample; i++) { + for (size_t j = 0; j < bytes_per_sample; j++) { + buf.at(bytes_per_sample*i + j) = source_buf.at(source_ix + j); + } + + // Do not advance the source index if the sample index is + // at the spots where we want to duplicate the source sample + if (not (i > 0 and (i % (valid_samples / missing_samples) == 0))) { + source_ix += bytes_per_sample; + } + } +} + /*! Wait the proper amount of time to throttle down to nominal encoding * rate, if drift compensation is enabled. */ -void drift_compensation_delay(int sample_rate, int channels, size_t bytes) +static void drift_compensation_delay(int sample_rate, int channels, size_t bytes) { const size_t bytes_per_second = sample_rate * BYTES_PER_SAMPLE * channels; @@ -684,7 +723,7 @@ int main(int argc, char *argv[]) } - std::vector<uint8_t> input_buf; + vec_u8 input_buf; HANDLE_AACENCODER encoder; @@ -843,8 +882,8 @@ int main(int argc, char *argv[]) #endif int outbuf_size; - std::vector<uint8_t> zmqframebuf; - std::vector<uint8_t> outbuf; + vec_u8 zmqframebuf; + vec_u8 outbuf; if (selected_encoder == encoder_selection_t::fdk_dabplus) { outbuf_size = bitrate/8*120; outbuf.resize(24*120); @@ -950,6 +989,7 @@ int main(int argc, char *argv[]) if (drift_compensation) { size_t overruns; size_t bytes_from_queue = queue.pop(&input_buf[0], input_buf.size(), &overruns); // returns bytes + expand_missing_samples(input_buf, channels, bytes_from_queue); read_bytes = input_buf.size(); drift_compensation_delay(sample_rate, channels, read_bytes); @@ -994,6 +1034,7 @@ int main(int argc, char *argv[]) size_t overruns; size_t bytes_from_queue = queue.pop(&input_buf[0], input_buf.size(), &overruns); // returns bytes + expand_missing_samples(input_buf, channels, bytes_from_queue); read_bytes = input_buf.size(); drift_compensation_delay(sample_rate, channels, read_bytes); |