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decoding to 32 bit

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This commit is contained in:
Hans Dijkema
2026-04-27 17:22:46 +02:00
parent 1a8646fd8b
commit 569ba05514
3 changed files with 532 additions and 573 deletions
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ffmpeg-audio/demo_ffmpeg_audio.c
+55 -89
View File
@@ -8,12 +8,14 @@
#define fprintf fprintf_s
#endif
static void write_u16_le(FILE *f, uint16_t v) {
static void write_u16_le(FILE *f, uint16_t v)
{
fputc((int)(v & 0xff), f);
fputc((int)((v >> 8) & 0xff), f);
}
static void write_u32_le(FILE *f, uint32_t v) {
static void write_u32_le(FILE *f, uint32_t v)
{
fputc((int)(v & 0xff), f);
fputc((int)((v >> 8) & 0xff), f);
fputc((int)((v >> 16) & 0xff), f);
@@ -24,7 +26,8 @@ static int write_wav_header(FILE *f,
int sample_rate,
int channels,
int bits_per_sample,
uint32_t data_size) {
uint32_t data_size)
{
const uint32_t byte_rate =
(uint32_t)(sample_rate * channels * bits_per_sample / 8);
const uint16_t block_align =
@@ -36,7 +39,7 @@ static int write_wav_header(FILE *f,
fwrite("fmt ", 1, 4, f);
write_u32_le(f, 16); /* fmt chunk size */
write_u16_le(f, 1); /* 1 = integer PCM */
write_u16_le(f, 1); /* PCM */
write_u16_le(f, (uint16_t)channels);
write_u32_le(f, (uint32_t)sample_rate);
write_u32_le(f, byte_rate);
@@ -53,7 +56,8 @@ static int rewrite_wav_header(FILE *f,
int sample_rate,
int channels,
int bits_per_sample,
uint32_t data_size) {
uint32_t data_size)
{
if (fseek(f, 0, SEEK_SET) != 0) {
return 0;
}
@@ -65,37 +69,24 @@ static int rewrite_wav_header(FILE *f,
data_size);
}
static int write_decoder_buffer(FILE *out,
fmpg_decoder *dec,
uint64_t *total_written) {
const uint8_t *buf = fmpg_decoder_buffer(dec);
const int size = fmpg_decoder_buffer_size(dec);
if (!buf || size <= 0) {
return 1;
static void print_if_present(const char *label, const char *value)
{
if (value && value[0]) {
printf("%s: %s\n", label, value);
}
if (fwrite(buf, 1, (size_t)size, out) != (size_t)size) {
return 0;
}
*total_written += (uint64_t)size;
return 1;
}
int main(int argc, char **argv) {
int main(int argc, char **argv)
{
const char *infile;
const char *outfile;
fmpg_instance *ac = NULL;
fmpg_decoder *dec = NULL;
fmpg_instance *fmpg = NULL;
FILE *out = NULL;
int sample_rate;
int channels;
int bits_per_sample;
int64_t duration_ms;
int64_t duration_samples;
uint64_t total_written = 0;
if (argc != 3) {
@@ -106,48 +97,38 @@ int main(int argc, char **argv) {
infile = argv[1];
outfile = argv[2];
ac = fmpg_init();
if (!ac) {
fprintf(stderr, "ac_init failed\n");
fmpg = fmpg_init();
if (!fmpg) {
fprintf(stderr, "fmpg_init failed\n");
return 1;
}
if (!fmpg_open_file(ac, infile)) {
if (!fmpg_open_file(fmpg, infile)) {
fprintf(stderr, "could not open input file: %s\n", infile);
fmpg_free(ac);
fmpg_free(fmpg);
return 1;
}
sample_rate = fmpg_audio_sample_rate(ac);
channels = fmpg_audio_channels(ac);
bits_per_sample = fmpg_audio_bits_per_sample(ac);
duration_ms = fmpg_duration_ms(ac);
duration_samples = fmpg_duration_samples(ac);
sample_rate = fmpg_audio_sample_rate(fmpg);
channels = fmpg_audio_channels(fmpg);
bits_per_sample = fmpg_audio_bits_per_sample(fmpg);
if (sample_rate <= 0 || channels <= 0 || bits_per_sample != 32) {
fprintf(stderr, "invalid audio parameters\n");
fmpg_free(ac);
return 1;
}
dec = fmpg_create_decoder(ac);
if (!dec) {
fprintf(stderr, "could not create decoder\n");
fmpg_free(ac);
fprintf(stderr, "unexpected audio format reported by decoder\n");
fmpg_free(fmpg);
return 1;
}
out = fopen(outfile, "wb");
if (!out) {
fprintf(stderr, "could not open output file: %s\n", outfile);
fmpg_free_decoder(dec);
fmpg_free(ac);
fmpg_free(fmpg);
return 1;
}
/*
* We do not know the final WAV data size yet.
* Write a placeholder header first and patch it at the end.
* The final WAV data size is only known after decoding. Write a temporary
* header now and patch it after the decode loop.
*/
if (!write_wav_header(out,
sample_rate,
@@ -156,44 +137,22 @@ int main(int argc, char **argv) {
0)) {
fprintf(stderr, "could not write WAV header\n");
fclose(out);
fmpg_free_decoder(dec);
fmpg_free(ac);
fmpg_free(fmpg);
return 1;
}
for (;;) {
fmpg_package *pkg = fmpg_read_package(ac);
while (fmpg_decode_next(fmpg)) {
const uint8_t *buf = fmpg_buffer(fmpg);
const int size = fmpg_buffer_size(fmpg);
if (!pkg) {
break;
}
/*
* ac_read_package() now returns only packets from the internally
* selected audio stream. No stream_index test is needed anymore.
*/
if (fmpg_decode_package(pkg, dec)) {
if (!write_decoder_buffer(out, dec, &total_written)) {
fprintf(stderr, "could not write PCM data\n");
fmpg_free_package(pkg);
if (buf && size > 0) {
if (fwrite(buf, 1, (size_t)size, out) != (size_t)size) {
fprintf(stderr, "write error\n");
fclose(out);
fmpg_free_decoder(dec);
fmpg_free(ac);
fmpg_free(fmpg);
return 1;
}
}
fmpg_free_package(pkg);
}
/* Drain delayed samples from the decoder and resampler. */
while (fmpg_flush_decoder(dec)) {
if (!write_decoder_buffer(out, dec, &total_written)) {
fprintf(stderr, "could not write flushed PCM data\n");
fclose(out);
fmpg_free_decoder(dec);
fmpg_free(ac);
return 1;
total_written += (uint64_t)size;
}
}
@@ -209,24 +168,31 @@ int main(int argc, char **argv) {
bits_per_sample,
(uint32_t)total_written)) {
fprintf(stderr, "could not rewrite WAV header\n");
fclose(out);
fmpg_free(fmpg);
return 1;
}
fclose(out);
printf("wrote %s\n", outfile);
printf("title: %s\n", fmpg_file_title(ac));
printf("album: %s\n", fmpg_file_album(ac));
printf("wrote: %s\n", outfile);
printf("sample rate: %d\n", sample_rate);
printf("channels: %d\n", channels);
printf("sample bits: %d\n", bits_per_sample);
printf("duration ms: %lld\n", (long long)duration_ms);
printf("duration smp:%lld\n", (long long)duration_samples);
printf("decoded smp: %lld\n", (long long)fmpg_decoder_sample_position(dec));
printf("data bytes: %llu\n",
(unsigned long long)total_written);
printf("data bytes: %llu\n", (unsigned long long)total_written);
printf("samples out: %lld\n", (long long)fmpg_sample_position(fmpg));
fmpg_free_decoder(dec);
fmpg_free(ac);
if (fmpg_duration_ms(fmpg) >= 0) {
printf("duration ms: %lld\n", (long long)fmpg_duration_ms(fmpg));
}
if (fmpg_duration_samples(fmpg) >= 0) {
printf("duration smp:%lld\n", (long long)fmpg_duration_samples(fmpg));
}
print_if_present("title", fmpg_file_title(fmpg));
print_if_present("artist", fmpg_file_author(fmpg));
print_if_present("album", fmpg_file_album(fmpg));
fmpg_free(fmpg);
return 0;
}