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vgmstream/src/coding/vorbis_custom_decoder.c

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#include <math.h>
#include "coding.h"
#include "vorbis_custom_decoder.h"
#ifdef VGM_USE_VORBIS
#define VORBIS_DEFAULT_BUFFER_SIZE 0x8000 /* should be at least the size of the setup header, ~0x2000 */
static void pcm_convert_float_to_16(sample_t* outbuf, int samples_to_do, float** pcm, int channels);
/**
* Inits a vorbis stream of some custom variety.
*
* Normally Vorbis packets are stored in .ogg, which is divided into OggS pages/packets, and the first packets contain necessary
* Vorbis setup. For custom vorbis the OggS layer is replaced/optimized, the setup can be modified or stored elsewhere
* (i.e.- in the .exe) and raw Vorbis packets may be modified as well, presumably to shave off some kb and/or obfuscate.
* We'll manually read/modify the data and decode it with libvorbis calls.
*
* Reference: https://www.xiph.org/vorbis/doc/libvorbis/overview.html
*/
vorbis_custom_codec_data* init_vorbis_custom(STREAMFILE* sf, off_t start_offset, vorbis_custom_t type, vorbis_custom_config* config) {
vorbis_custom_codec_data* data = NULL;
int ok;
/* init stuff */
data = calloc(1,sizeof(vorbis_custom_codec_data));
if (!data) goto fail;
data->buffer_size = VORBIS_DEFAULT_BUFFER_SIZE;
data->buffer = calloc(sizeof(uint8_t), data->buffer_size);
if (!data->buffer) goto fail;
/* keep around to decode too */
data->type = type;
memcpy(&data->config, config, sizeof(vorbis_custom_config));
/* init vorbis stream state, using 3 fake Ogg setup packets (info, comments, setup/codebooks)
* libvorbis expects parsed Ogg pages, but we'll fake them with our raw data instead */
vorbis_info_init(&data->vi);
vorbis_comment_init(&data->vc);
data->op.packet = data->buffer;
data->op.b_o_s = 1; /* fake headers start */
/* init header */
switch(data->type) {
case VORBIS_FSB: ok = vorbis_custom_setup_init_fsb(sf, start_offset, data); break;
case VORBIS_WWISE: ok = vorbis_custom_setup_init_wwise(sf, start_offset, data); break;
case VORBIS_OGL: ok = vorbis_custom_setup_init_ogl(sf, start_offset, data); break;
case VORBIS_SK: ok = vorbis_custom_setup_init_sk(sf, start_offset, data); break;
case VORBIS_VID1: ok = vorbis_custom_setup_init_vid1(sf, start_offset, data); break;
case VORBIS_AWC: ok = vorbis_custom_setup_init_awc(sf, start_offset, data); break;
default: goto fail;
}
if(!ok) goto fail;
data->op.b_o_s = 0; /* end of fake headers */
/* init vorbis global and block state */
if (vorbis_synthesis_init(&data->vd,&data->vi) != 0) goto fail;
if (vorbis_block_init(&data->vd,&data->vb) != 0) goto fail;
/* write output */
config->data_start_offset = data->config.data_start_offset;
if (!data->config.stream_end) {
data->config.stream_end = get_streamfile_size(sf);
}
return data;
fail:
VGM_LOG("VORBIS: init fail at around 0x%x\n", (uint32_t)start_offset);
free_vorbis_custom(data);
return NULL;
}
/* Decodes Vorbis packets into a libvorbis sample buffer, and copies them to outbuf */
void decode_vorbis_custom(VGMSTREAM* vgmstream, sample_t* outbuf, int32_t samples_to_do, int channels) {
VGMSTREAMCHANNEL *stream = &vgmstream->ch[0];
vorbis_custom_codec_data* data = vgmstream->codec_data;
//data->op.packet = data->buffer;/* implicit from init */
int samples_done = 0;
while (samples_done < samples_to_do) {
if (data->samples_full) { /* read more samples */
int samples_to_get;
float **pcm;
/* get PCM samples from libvorbis buffers */
samples_to_get = vorbis_synthesis_pcmout(&data->vd, &pcm);
if (!samples_to_get) {
data->samples_full = 0; /* request more if empty*/
continue;
}
if (data->samples_to_discard) {
/* discard samples for looping */
if (samples_to_get > data->samples_to_discard)
samples_to_get = data->samples_to_discard;
data->samples_to_discard -= samples_to_get;
}
else {
/* get max samples and convert from Vorbis float pcm to 16bit pcm */
if (samples_to_get > samples_to_do - samples_done)
samples_to_get = samples_to_do - samples_done;
pcm_convert_float_to_16(outbuf + samples_done * channels, samples_to_get, pcm, data->vi.channels);
samples_done += samples_to_get;
}
/* mark consumed samples from the buffer
* (non-consumed samples are returned in next vorbis_synthesis_pcmout calls) */
vorbis_synthesis_read(&data->vd, samples_to_get);
}
else { /* read more data */
int ok, rc;
/* extra EOF check */
if (stream->offset >= data->config.stream_end) {
/* may need to drain samples? (not a thing in vorbis due to packet types?) */
goto decode_fail;
}
/* not actually needed, but feels nicer */
data->op.granulepos += samples_to_do; /* can be changed next if desired */
data->op.packetno++;
/* read/transform data into the ogg_packet buffer and advance offsets */
switch(data->type) {
case VORBIS_FSB: ok = vorbis_custom_parse_packet_fsb(stream, data); break;
case VORBIS_WWISE: ok = vorbis_custom_parse_packet_wwise(stream, data); break;
case VORBIS_OGL: ok = vorbis_custom_parse_packet_ogl(stream, data); break;
case VORBIS_SK: ok = vorbis_custom_parse_packet_sk(stream, data); break;
case VORBIS_VID1: ok = vorbis_custom_parse_packet_vid1(stream, data); break;
case VORBIS_AWC: ok = vorbis_custom_parse_packet_awc(stream, data); break;
default: goto decode_fail;
}
if(!ok) {
goto decode_fail;
}
/* parse the fake ogg packet into a logical vorbis block */
rc = vorbis_synthesis(&data->vb,&data->op);
if (rc == OV_ENOTAUDIO) {
VGM_LOG("Vorbis: not an audio packet (size=0x%x) @ %x\n",(size_t)data->op.bytes,(uint32_t)stream->offset);
//VGM_LOGB(data->op.packet, (size_t)data->op.bytes,0);
continue; /* rarely happens, seems ok? */
} else if (rc != 0) goto decode_fail;
/* finally decode the logical block into samples */
rc = vorbis_synthesis_blockin(&data->vd,&data->vb);
if (rc != 0) goto decode_fail; /* ? */
data->samples_full = 1;
}
}
return;
decode_fail:
/* on error just put some 0 samples */
VGM_LOG("VORBIS: decode fail at %x, missing %i samples\n", (uint32_t)stream->offset, (samples_to_do - samples_done));
memset(outbuf + samples_done * channels, 0, (samples_to_do - samples_done) * channels * sizeof(sample));
}
/* converts from internal Vorbis format to standard PCM (mostly from Xiph's decoder_example.c) */
static void pcm_convert_float_to_16(sample_t* outbuf, int samples_to_do, float** pcm, int channels) {
int ch, s;
sample_t* ptr;
float* channel;
/* convert float PCM (multichannel float array, with pcm[0]=ch0, pcm[1]=ch1, pcm[2]=ch0, etc)
* to 16 bit signed PCM ints (host order) and interleave + fix clipping */
for (ch = 0; ch < channels; ch++) {
/* channels should be in standard order unlike Ogg Vorbis (at least in FSB) */
ptr = outbuf + ch;
channel = pcm[ch];
for (s = 0; s < samples_to_do; s++) {
int val = (int)floor(channel[s] * 32767.0f + 0.5f);
if (val > 32767) val = 32767;
else if (val < -32768) val = -32768;
*ptr = val;
ptr += channels;
}
}
}
/* ********************************************** */
void free_vorbis_custom(vorbis_custom_codec_data* data) {
if (!data)
return;
/* internal decoder cleanup */
vorbis_block_clear(&data->vb);
vorbis_dsp_clear(&data->vd);
vorbis_comment_clear(&data->vc);
vorbis_info_clear(&data->vi);
free(data->buffer);
free(data);
}
void reset_vorbis_custom(VGMSTREAM* vgmstream) {
vorbis_custom_codec_data *data = vgmstream->codec_data;
if (!data) return;
vorbis_synthesis_restart(&data->vd);
data->samples_to_discard = 0;
}
void seek_vorbis_custom(VGMSTREAM* vgmstream, int32_t num_sample) {
vorbis_custom_codec_data *data = vgmstream->codec_data;
if (!data) return;
/* Seeking is provided by the Ogg layer, so with custom vorbis we'd need seek tables instead.
* To avoid having to parse different formats we'll just discard until the expected sample */
vorbis_synthesis_restart(&data->vd);
data->samples_to_discard = num_sample;
if (vgmstream->loop_ch)
vgmstream->loop_ch[0].offset = vgmstream->loop_ch[0].channel_start_offset;
}
#endif
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