MrBesen/ffmpeg
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity
ecb5546e97
ffmpeg/libavcodec/vc2enc_dwt.c
Rostislav Pehlivanov 3228ac730c vc2enc_dwt: pad the temporary buffer by the slice size 
Since non-Haar wavelets need to look into pixels outside the frame, we
need to pad the buffer. The old factor of two seemed to be a workaround
that fact and only padded to the left and bottom. This correctly pads
by the slice size and as such reduces memory usage and potential
exploits.
Reported by Liu Bingchang.

Ideally, there should be no temporary buffer but the encoder is designed
to deinterleave the coefficients into the classical wavelet structure
with the lower frequency values in the top left corner.

Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>
2017-11-09 00:05:48 +00:00

282 lines
10 KiB
C
Raw Blame History

/*
* Copyright (C) 2007 Marco Gerards <marco@gnu.org>
* Copyright (C) 2016 Open Broadcast Systems Ltd.
* Author 2016 Rostislav Pehlivanov <atomnuker@gmail.com>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/attributes.h"
#include "libavutil/mem.h"
#include "vc2enc_dwt.h"
/* Since the transforms spit out interleaved coefficients, this function
* rearranges the coefficients into the more traditional subdivision,
* making it easier to encode and perform another level. */
static av_always_inline void deinterleave(dwtcoef *linell, ptrdiff_t stride,
int width, int height, dwtcoef *synthl)
{
int x, y;
ptrdiff_t synthw = width << 1;
dwtcoef *linehl = linell + width;
dwtcoef *linelh = linell + height*stride;
dwtcoef *linehh = linelh + width;
/* Deinterleave the coefficients. */
for (y = 0; y < height; y++) {
for (x = 0; x < width; x++) {
linell[x] = synthl[(x << 1)];
linehl[x] = synthl[(x << 1) + 1];
linelh[x] = synthl[(x << 1) + synthw];
linehh[x] = synthl[(x << 1) + synthw + 1];
}
synthl += synthw << 1;
linell += stride;
linelh += stride;
linehl += stride;
linehh += stride;
}
}
static void vc2_subband_dwt_97(VC2TransformContext *t, dwtcoef *data,
ptrdiff_t stride, int width, int height)
{
int x, y;
dwtcoef *datal = data, *synth = t->buffer, *synthl = synth;
const ptrdiff_t synth_width = width << 1;
const ptrdiff_t synth_height = height << 1;
/*
* Shift in one bit that is used for additional precision and copy
* the data to the buffer.
*/
for (y = 0; y < synth_height; y++) {
for (x = 0; x < synth_width; x++)
synthl[x] = datal[x] << 1;
synthl += synth_width;
datal += stride;
}
/* Horizontal synthesis. */
synthl = synth;
for (y = 0; y < synth_height; y++) {
/* Lifting stage 2. */
synthl[1] -= (8*synthl[0] + 9*synthl[2] - synthl[4] + 8) >> 4;
for (x = 1; x < width - 2; x++)
synthl[2*x + 1] -= (9*synthl[2*x] + 9*synthl[2*x + 2] - synthl[2*x + 4] -
synthl[2 * x - 2] + 8) >> 4;
synthl[synth_width - 1] -= (17*synthl[synth_width - 2] -
synthl[synth_width - 4] + 8) >> 4;
synthl[synth_width - 3] -= (8*synthl[synth_width - 2] +
9*synthl[synth_width - 4] -
synthl[synth_width - 6] + 8) >> 4;
/* Lifting stage 1. */
synthl[0] += (synthl[1] + synthl[1] + 2) >> 2;
for (x = 1; x < width - 1; x++)
synthl[2*x] += (synthl[2*x - 1] + synthl[2*x + 1] + 2) >> 2;
synthl[synth_width - 2] += (synthl[synth_width - 3] +
synthl[synth_width - 1] + 2) >> 2;
synthl += synth_width;
}
/* Vertical synthesis: Lifting stage 2. */
synthl = synth + synth_width;
for (x = 0; x < synth_width; x++)
synthl[x] -= (8*synthl[x - synth_width] + 9*synthl[x + synth_width] -
synthl[x + 3 * synth_width] + 8) >> 4;
synthl = synth + (synth_width << 1);
for (y = 1; y < height - 2; y++) {
for (x = 0; x < synth_width; x++)
synthl[x + synth_width] -= (9*synthl[x] +
9*synthl[x + 2 * synth_width] -
synthl[x - 2 * synth_width] -
synthl[x + 4 * synth_width] + 8) >> 4;
synthl += synth_width << 1;
}
synthl = synth + (synth_height - 1) * synth_width;
for (x = 0; x < synth_width; x++) {
synthl[x] -= (17*synthl[x - synth_width] -
synthl[x - 3*synth_width] + 8) >> 4;
synthl[x - 2*synth_width] -= (9*synthl[x - 3*synth_width] +
8*synthl[x - 1*synth_width] - synthl[x - 5*synth_width] + 8) >> 4;
}
/* Vertical synthesis: Lifting stage 1. */
synthl = synth;
for (x = 0; x < synth_width; x++)
synthl[x] += (synthl[x + synth_width] + synthl[x + synth_width] + 2) >> 2;
synthl = synth + (synth_width << 1);
for (y = 1; y < height - 1; y++) {
for (x = 0; x < synth_width; x++)
synthl[x] += (synthl[x - synth_width] + synthl[x + synth_width] + 2) >> 2;
synthl += synth_width << 1;
}
synthl = synth + (synth_height - 2) * synth_width;
for (x = 0; x < synth_width; x++)
synthl[x] += (synthl[x - synth_width] + synthl[x + synth_width] + 2) >> 2;
deinterleave(data, stride, width, height, synth);
}
static void vc2_subband_dwt_53(VC2TransformContext *t, dwtcoef *data,
ptrdiff_t stride, int width, int height)
{
int x, y;
dwtcoef *synth = t->buffer, *synthl = synth, *datal = data;
const ptrdiff_t synth_width = width << 1;
const ptrdiff_t synth_height = height << 1;
/*
* Shift in one bit that is used for additional precision and copy
* the data to the buffer.
*/
for (y = 0; y < synth_height; y++) {
for (x = 0; x < synth_width; x++)
synthl[x] = datal[x] << 1;
synthl += synth_width;
datal += stride;
}
/* Horizontal synthesis. */
synthl = synth;
for (y = 0; y < synth_height; y++) {
/* Lifting stage 2. */
for (x = 0; x < width - 1; x++)
synthl[2 * x + 1] -= (synthl[2 * x] + synthl[2 * x + 2] + 1) >> 1;
synthl[synth_width - 1] -= (2*synthl[synth_width - 2] + 1) >> 1;
/* Lifting stage 1. */
synthl[0] += (2*synthl[1] + 2) >> 2;
for (x = 1; x < width - 1; x++)
synthl[2 * x] += (synthl[2 * x - 1] + synthl[2 * x + 1] + 2) >> 2;
synthl[synth_width - 2] += (synthl[synth_width - 3] + synthl[synth_width - 1] + 2) >> 2;
synthl += synth_width;
}
/* Vertical synthesis: Lifting stage 2. */
synthl = synth + synth_width;
for (x = 0; x < synth_width; x++)
synthl[x] -= (synthl[x - synth_width] + synthl[x + synth_width] + 1) >> 1;
synthl = synth + (synth_width << 1);
for (y = 1; y < height - 1; y++) {
for (x = 0; x < synth_width; x++)
synthl[x + synth_width] -= (synthl[x] + synthl[x + synth_width * 2] + 1) >> 1;
synthl += (synth_width << 1);
}
synthl = synth + (synth_height - 1) * synth_width;
for (x = 0; x < synth_width; x++)
synthl[x] -= (2*synthl[x - synth_width] + 1) >> 1;
/* Vertical synthesis: Lifting stage 1. */
synthl = synth;
for (x = 0; x < synth_width; x++)
synthl[x] += (2*synthl[synth_width + x] + 2) >> 2;
synthl = synth + (synth_width << 1);
for (y = 1; y < height - 1; y++) {
for (x = 0; x < synth_width; x++)
synthl[x] += (synthl[x + synth_width] + synthl[x - synth_width] + 2) >> 2;
synthl += (synth_width << 1);
}
synthl = synth + (synth_height - 2)*synth_width;
for (x = 0; x < synth_width; x++)
synthl[x] += (synthl[x - synth_width] + synthl[x + synth_width] + 2) >> 2;
deinterleave(data, stride, width, height, synth);
}
static av_always_inline void dwt_haar(VC2TransformContext *t, dwtcoef *data,
ptrdiff_t stride, int width, int height,
const int s)
{
int x, y;
dwtcoef *synth = t->buffer, *synthl = synth, *datal = data;
const ptrdiff_t synth_width = width << 1;
const ptrdiff_t synth_height = height << 1;
/* Horizontal synthesis. */
for (y = 0; y < synth_height; y++) {
for (x = 0; x < synth_width; x += 2) {
synthl[y*synth_width + x + 1] = (datal[y*stride + x + 1] << s) -
(datal[y*stride + x] << s);
synthl[y*synth_width + x] = (datal[y*stride + x + 0] << s) +
((synthl[y*synth_width + x + 1] + 1) >> 1);
}
}
/* Vertical synthesis. */
for (x = 0; x < synth_width; x++) {
for (y = 0; y < synth_height; y += 2) {
synthl[(y + 1)*synth_width + x] = synthl[(y + 1)*synth_width + x] -
synthl[y*synth_width + x];
synthl[y*synth_width + x] = synthl[y*synth_width + x] +
((synthl[(y + 1)*synth_width + x] + 1) >> 1);
}
}
deinterleave(data, stride, width, height, synth);
}
static void vc2_subband_dwt_haar(VC2TransformContext *t, dwtcoef *data,
ptrdiff_t stride, int width, int height)
{
dwt_haar(t, data, stride, width, height, 0);
}
static void vc2_subband_dwt_haar_shift(VC2TransformContext *t, dwtcoef *data,
ptrdiff_t stride, int width, int height)
{
dwt_haar(t, data, stride, width, height, 1);
}
av_cold int ff_vc2enc_init_transforms(VC2TransformContext *s, int p_stride,
int p_height, int slice_w, int slice_h)
{
s->vc2_subband_dwt[VC2_TRANSFORM_9_7] = vc2_subband_dwt_97;
s->vc2_subband_dwt[VC2_TRANSFORM_5_3] = vc2_subband_dwt_53;
s->vc2_subband_dwt[VC2_TRANSFORM_HAAR] = vc2_subband_dwt_haar;
s->vc2_subband_dwt[VC2_TRANSFORM_HAAR_S] = vc2_subband_dwt_haar_shift;
/* Pad by the slice size, only matters for non-Haar wavelets */
s->buffer = av_calloc((p_stride + slice_w)*(p_height + slice_h), sizeof(dwtcoef));
if (!s->buffer)
return 1;
s->padding = (slice_h >> 1)*p_stride + (slice_w >> 1);
s->buffer += s->padding;
return 0;
}
av_cold void ff_vc2enc_free_transforms(VC2TransformContext *s)
{
av_free(s->buffer - s->padding);
s->buffer = NULL;
}
Reference in New Issue View Git Blame Copy Permalink