gstreamer/gst-libs/gst/codecparsers/gstvp8rangedecoder.c

63 lines
1.6 KiB
C
Raw Normal View History

/*
* gstvp8rangedecoder.c - VP8 range decoder interface
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "gstvp8rangedecoder.h"
#include "dboolhuff.h"
#define BOOL_DECODER_CAST(rd) \
((BOOL_DECODER *)(&(rd)->_gst_reserved[1]))
gboolean
gst_vp8_range_decoder_init (GstVp8RangeDecoder * rd, const guchar * buf,
guint buf_size)
{
BOOL_DECODER *const bd = BOOL_DECODER_CAST (rd);
g_return_val_if_fail (sizeof (rd->_gst_reserved) >= sizeof (*bd), FALSE);
rd->buf = buf;
rd->buf_size = buf_size;
return vp8dx_start_decode (bd, buf, buf_size, NULL, NULL) == 0;
}
gint
gst_vp8_range_decoder_read (GstVp8RangeDecoder * rd, guint8 prob)
{
return vp8dx_decode_bool (BOOL_DECODER_CAST (rd), prob);
}
gint
gst_vp8_range_decoder_read_literal (GstVp8RangeDecoder * rd, gint bits)
{
return vp8_decode_value (BOOL_DECODER_CAST (rd), bits);
}
guint
gst_vp8_range_decoder_get_pos (GstVp8RangeDecoder * rd)
{
BOOL_DECODER *const bd = BOOL_DECODER_CAST (rd);
return (bd->user_buffer - rd->buf) * 8 - (8 + bd->count);
}
void
gst_vp8_range_decoder_get_state (GstVp8RangeDecoder * rd,
GstVp8RangeDecoderState * state)
{
BOOL_DECODER *const bd = BOOL_DECODER_CAST (rd);
if (bd->count < 0)
vp8dx_bool_decoder_fill (bd);
state->range = bd->range;
state->value = (guint8) ((bd->value) >> (VP8_BD_VALUE_SIZE - 8));
state->count = (8 + bd->count) % 8;
}