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/*
* VBLE Decoder
* Copyright (c) 2011 Derek Buitenhuis
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* VBLE Decoder
*/
#define BITSTREAM_READER_LE
#include "avcodec.h"
#include "dsputil.h"
#include "get_bits.h"
#include "internal.h"
#include "mathops.h"
typedef struct {
AVCodecContext *avctx;
DSPContext dsp;
int size;
uint8_t *val; /* First holds the lengths of vlc symbols and then their values */
} VBLEContext;
static uint8_t vble_read_reverse_unary(GetBitContext *gb)
{
/* At most we need to read 9 bits total to get indices up to 8 */
uint8_t val = show_bits(gb, 8);
if (val) {
val = 7 - av_log2_16bit(ff_reverse[val]);
skip_bits(gb, val + 1);
return val;
} else {
skip_bits(gb, 8);
if (get_bits1(gb))
return 8;
}
/* Return something larger than 8 on error */
return UINT8_MAX;
}
static int vble_unpack(VBLEContext *ctx, GetBitContext *gb)
{
int i;
/* Read all the lengths in first */
for (i = 0; i < ctx->size; i++) {
ctx->val[i] = vble_read_reverse_unary(gb);
if (ctx->val[i] == UINT8_MAX)
return -1;
}
for (i = 0; i < ctx->size; i++) {
/* Check we have enough bits left */
if (get_bits_left(gb) < ctx->val[i])
return -1;
/* get_bits can't take a length of 0 */
if (ctx->val[i])
ctx->val[i] = (1 << ctx->val[i]) + get_bits(gb, ctx->val[i]) - 1;
}
return 0;
}
static void vble_restore_plane(VBLEContext *ctx, AVFrame *pic,
int plane, int offset,
int width, int height)
{
uint8_t *dst = pic->data[plane];
uint8_t *val = ctx->val + offset;
int stride = pic->linesize[plane];
int i, j, left, left_top;
for (i = 0; i < height; i++) {
for (j = 0; j < width; j++)
val[j] = (val[j] >> 1) ^ -(val[j] & 1);
if (i) {
left = 0;
left_top = dst[-stride];
ctx->dsp.add_hfyu_median_prediction(dst, dst-stride, val,
width, &left, &left_top);
} else {
dst[0] = val[0];
for (j = 1; j < width; j++)
dst[j] = val[j] + dst[j - 1];
}
dst += stride;
val += width;
}
}
static int vble_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
AVPacket *avpkt)
{
VBLEContext *ctx = avctx->priv_data;
AVFrame *pic = data;
GetBitContext gb;
const uint8_t *src = avpkt->data;
int version;
int offset = 0;
int width_uv = avctx->width / 2, height_uv = avctx->height / 2;
/* Allocate buffer */
if (ff_get_buffer(avctx, pic, 0) < 0) {
av_log(avctx, AV_LOG_ERROR, "Could not allocate buffer.\n");
return AVERROR(ENOMEM);
}
/* Set flags */
pic->key_frame = 1;
pic->pict_type = AV_PICTURE_TYPE_I;
/* Version should always be 1 */
version = AV_RL32(src);
if (version != 1)
av_log(avctx, AV_LOG_WARNING, "Unsupported VBLE Version: %d\n", version);
init_get_bits(&gb, src + 4, (avpkt->size - 4) * 8);
/* Unpack */
if (vble_unpack(ctx, &gb) < 0) {
av_log(avctx, AV_LOG_ERROR, "Invalid Code\n");
return AVERROR_INVALIDDATA;
}
/* Restore planes. Should be almost identical to Huffyuv's. */
vble_restore_plane(ctx, pic, 0, offset, avctx->width, avctx->height);
/* Chroma */
if (!(ctx->avctx->flags & CODEC_FLAG_GRAY)) {
offset += avctx->width * avctx->height;
vble_restore_plane(ctx, pic, 1, offset, width_uv, height_uv);
offset += width_uv * height_uv;
vble_restore_plane(ctx, pic, 2, offset, width_uv, height_uv);
}
*got_frame = 1;
return avpkt->size;
}
static av_cold int vble_decode_close(AVCodecContext *avctx)
{
VBLEContext *ctx = avctx->priv_data;
av_freep(&ctx->val);
return 0;
}
static av_cold int vble_decode_init(AVCodecContext *avctx)
{
VBLEContext *ctx = avctx->priv_data;
/* Stash for later use */
ctx->avctx = avctx;
ff_dsputil_init(&ctx->dsp, avctx);
avctx->pix_fmt = AV_PIX_FMT_YUV420P;
avctx->bits_per_raw_sample = 8;
ctx->size = avpicture_get_size(avctx->pix_fmt,
avctx->width, avctx->height);
ctx->val = av_malloc(ctx->size * sizeof(*ctx->val));
if (!ctx->val) {
av_log(avctx, AV_LOG_ERROR, "Could not allocate values buffer.\n");
vble_decode_close(avctx);
return AVERROR(ENOMEM);
}
return 0;
}
AVCodec ff_vble_decoder = {
.name = "vble",
.long_name = NULL_IF_CONFIG_SMALL("VBLE Lossless Codec"),
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_VBLE,
.priv_data_size = sizeof(VBLEContext),
.init = vble_decode_init,
.close = vble_decode_close,
.decode = vble_decode_frame,
.capabilities = CODEC_CAP_DR1,
};
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