Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

229 lines (190 sloc) 6.744 kb
/*
* 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 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 = AV_PICTURE_TYPE_I;
/* 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;
ff_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 = 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,
.long_name = NULL_IF_CONFIG_SMALL("VBLE Lossless Codec"),
};
Jump to Line
Something went wrong with that request. Please try again.