mirror of
https://github.com/KolibriOS/kolibrios.git
synced 2024-12-15 03:12:35 +03:00
120 lines
4.2 KiB
C
120 lines
4.2 KiB
C
/*
|
|
sampleadjust: gapless sample offset math
|
|
|
|
copyright 1995-2012 by the mpg123 project - free software under the terms of the LGPL 2.1
|
|
see COPYING and AUTHORS files in distribution or http://mpg123.org
|
|
|
|
This is no stand-alone header, precisely to be able to fool it into using fake handle types for testing the math.
|
|
*/
|
|
|
|
#include "debug.h"
|
|
|
|
#ifdef GAPLESS
|
|
/* From internal sample number to external. */
|
|
static off_t sample_adjust(mpg123_handle *mh, off_t x)
|
|
{
|
|
off_t s;
|
|
if(mh->p.flags & MPG123_GAPLESS)
|
|
{
|
|
/* It's a bit tricky to do this computation for the padding samples.
|
|
They are not there on the outside. */
|
|
if(x > mh->end_os)
|
|
{
|
|
if(x < mh->fullend_os)
|
|
s = mh->end_os - mh->begin_os;
|
|
else
|
|
s = x - (mh->fullend_os - mh->end_os + mh->begin_os);
|
|
}
|
|
else
|
|
s = x - mh->begin_os;
|
|
}
|
|
else
|
|
s = x;
|
|
|
|
return s;
|
|
}
|
|
|
|
/* from external samples to internal */
|
|
static off_t sample_unadjust(mpg123_handle *mh, off_t x)
|
|
{
|
|
off_t s;
|
|
if(mh->p.flags & MPG123_GAPLESS)
|
|
{
|
|
s = x + mh->begin_os;
|
|
/* There is a hole; we don't create sample positions in there.
|
|
Jump from the end of the gapless track directly to after the padding. */
|
|
if(s >= mh->end_os)
|
|
s += mh->fullend_os - mh->end_os;
|
|
}
|
|
else s = x;
|
|
|
|
return s;
|
|
}
|
|
|
|
/*
|
|
Take the buffer after a frame decode (strictly: it is the data from frame fr->num!) and cut samples out.
|
|
fr->buffer.fill may then be smaller than before...
|
|
*/
|
|
static void frame_buffercheck(mpg123_handle *fr)
|
|
{
|
|
/* When we have no accurate position, gapless code does not make sense. */
|
|
if(!(fr->state_flags & FRAME_ACCURATE)) return;
|
|
|
|
/* Get a grip on dirty streams that start with a gapless header.
|
|
Simply accept all data from frames that are too much,
|
|
they are supposedly attached to the stream after the fact. */
|
|
if(fr->gapless_frames > 0 && fr->num >= fr->gapless_frames) return;
|
|
|
|
/* Important: We first cut samples from the end, then cut from beginning (including left-shift of the buffer).
|
|
This order works also for the case where firstframe == lastframe. */
|
|
|
|
/* The last interesting (planned) frame: Only use some leading samples.
|
|
Note a difference from the below: The last frame and offset are unchanges by seeks.
|
|
The lastoff keeps being valid. */
|
|
if(fr->lastframe > -1 && fr->num >= fr->lastframe)
|
|
{
|
|
/* There can be more than one frame of padding at the end, so we ignore the whole frame if we are beyond lastframe. */
|
|
off_t byteoff = (fr->num == fr->lastframe) ? samples_to_bytes(fr, fr->lastoff) : 0;
|
|
if((off_t)fr->buffer.fill > byteoff)
|
|
{
|
|
fr->buffer.fill = byteoff;
|
|
}
|
|
if(VERBOSE3) fprintf(stderr, "\nNote: Cut frame %"OFF_P" buffer on end of stream to %"OFF_P" samples, fill now %"SIZE_P" bytes.\n", (off_p)fr->num, (off_p)(fr->num == fr->lastframe ? fr->lastoff : 0), (size_p)fr->buffer.fill);
|
|
}
|
|
|
|
/* The first interesting frame: Skip some leading samples. */
|
|
if(fr->firstoff && fr->num == fr->firstframe)
|
|
{
|
|
off_t byteoff = samples_to_bytes(fr, fr->firstoff);
|
|
if((off_t)fr->buffer.fill > byteoff)
|
|
{
|
|
fr->buffer.fill -= byteoff;
|
|
/* buffer.p != buffer.data only for own buffer */
|
|
debug6("cutting %li samples/%li bytes on begin, own_buffer=%i at %p=%p, buf[1]=%i",
|
|
(long)fr->firstoff, (long)byteoff, fr->own_buffer, (void*)fr->buffer.p, (void*)fr->buffer.data, ((short*)fr->buffer.p)[2]);
|
|
if(fr->own_buffer) fr->buffer.p = fr->buffer.data + byteoff;
|
|
else memmove(fr->buffer.data, fr->buffer.data + byteoff, fr->buffer.fill);
|
|
debug3("done cutting, buffer at %p =? %p, buf[1]=%i",
|
|
(void*)fr->buffer.p, (void*)fr->buffer.data, ((short*)fr->buffer.p)[2]);
|
|
}
|
|
else fr->buffer.fill = 0;
|
|
|
|
if(VERBOSE3) fprintf(stderr, "\nNote: Cut frame %"OFF_P" buffer on beginning of stream by %"OFF_P" samples, fill now %"SIZE_P" bytes.\n", (off_p)fr->num, (off_p)fr->firstoff, (size_p)fr->buffer.fill);
|
|
/* We can only reach this frame again by seeking. And on seeking, firstoff will be recomputed.
|
|
So it is safe to null it here (and it makes the if() decision abort earlier). */
|
|
fr->firstoff = 0;
|
|
}
|
|
}
|
|
|
|
#define SAMPLE_ADJUST(mh,x) sample_adjust(mh,x)
|
|
#define SAMPLE_UNADJUST(mh,x) sample_unadjust(mh,x)
|
|
#define FRAME_BUFFERCHECK(mh) frame_buffercheck(mh)
|
|
|
|
#else /* no gapless code included */
|
|
|
|
#define SAMPLE_ADJUST(mh,x) (x)
|
|
#define SAMPLE_UNADJUST(mh,x) (x)
|
|
#define FRAME_BUFFERCHECK(mh)
|
|
|
|
#endif
|