/*
* VBLE Decoder
* Copyright (c) 2011 Derek Buitenhuis
*
* 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
*/
/**
* @file
* VBLE Decoder
*/
#define ALT_BITSTREAM_READER_LE
#include "avcodec.h"
#include "dsputil.h"
#include "get_bits.h"
typedef struct {
AVCodecContext *avctx;
DSPContext dsp;
int size;
uint8_t *val; ///< This array first holds the lengths of vlc symbols and then their value.
} VBLEContext;
static int vble_unpack(VBLEContext *ctx, GetBitContext *gb)
{
int i;
int allbits = 0;
static const uint8_t LUT[256] = {
8,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
5,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
6,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
5,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
7,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
5,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
6,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
5,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,
};
/* Read all the lengths in first */
for (i = 0; i < ctx->size; i++) {
/* At most we need to read 9 bits total to get indices up to 8 */
int val = show_bits(gb, 8);
// read reverse unary
if (val) {
val = LUT[val];
skip_bits(gb, val + 1);
ctx->val[i] = val;
} else {
skip_bits(gb, 8);
if (!get_bits1(gb))
return -1;
ctx->val[i] = 8;
}
allbits += ctx->val[i];
}
/* Check we have enough bits left */
if (get_bits_left(gb) < allbits)
return -1;
return 0;
}
static void vble_restore_plane(VBLEContext *ctx, GetBitContext *gb, int plane,
int offset, int width, int height)
{
AVFrame *pic = ctx->avctx->coded_frame;
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++) {
/* get_bits can't take a length of 0 */
if (val[j]) {
int v = (1 << val[j]) + get_bits(gb, val[j]) - 1;
val[j] = (v >> 1) ^ -(v & 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 *data_size,
AVPacket *avpkt)
{
VBLEContext *ctx = avctx->priv_data;
AVFrame *pic = avctx->coded_frame;
GetBitContext gb;
const uint8_t *src = avpkt->data;
int version;
int offset = 0;
int width_uv = avctx->width / 2, height_uv = avctx->height / 2;
pic->reference = 0;
/* Clear buffer if need be */
if (pic->data[0])
avctx->release_buffer(avctx, pic);
/* Allocate buffer */
if (avctx->get_buffer(avctx, pic) < 0) {
av_log(avctx, AV_LOG_ERROR, "Could not allocate buffer.\n");
return AVERROR(ENOMEM);
}
/* Set flags */
pic->key_frame = 1;
pic->pict_type = FF_I_TYPE;
/* Version should always be 1 */
version = AV_RL32(src);
if (version != 1) {
av_log(avctx, AV_LOG_ERROR, "Unsupported VBLE Version: %d\n", version);
return AVERROR_INVALIDDATA;
}
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, &gb, 0, offset, avctx->width, avctx->height);
/* Chroma */
if (!(ctx->avctx->flags & CODEC_FLAG_GRAY)) {
offset += avctx->width * avctx->height;
vble_restore_plane(ctx, &gb, 1, offset, width_uv, height_uv);
offset += width_uv * height_uv;
vble_restore_plane(ctx, &gb, 2, offset, width_uv, height_uv);
}
*data_size = sizeof(AVFrame);
*(AVFrame *)data = *pic;
return avpkt->size;
}
static av_cold int vble_decode_close(AVCodecContext *avctx)
{
VBLEContext *ctx = avctx->priv_data;
AVFrame *pic = avctx->coded_frame;
if (pic->data[0])
avctx->release_buffer(avctx, pic);
av_freep(&avctx->coded_frame);
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;
dsputil_init(&ctx->dsp, avctx);
avctx->pix_fmt = PIX_FMT_YUV420P;
avctx->bits_per_raw_sample = 8;
avctx->coded_frame = avcodec_alloc_frame();
if (!avctx->coded_frame) {
av_log(avctx, AV_LOG_ERROR, "Could not allocate frame.\n");
return AVERROR(ENOMEM);
}
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",
.type = AVMEDIA_TYPE_VIDEO,
.id = CODEC_ID_VBLE,
.priv_data_size = sizeof(VBLEContext),
.init = vble_decode_init,
.close = vble_decode_close,
.decode = vble_decode_frame,
.capabilities = CODEC_CAP_DR1,
.long_name = NULL_IF_CONFIG_SMALL("VBLE Lossless Codec"),
};