1/*
2 * VBLE Decoder
3 * Copyright (c) 2011 Derek Buitenhuis
4 *
5 * This file is part of Libav.
6 *
7 * Libav is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * Libav is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22/**
23 * @file
24 * VBLE Decoder
25 */
26
27#define BITSTREAM_READER_LE
28
29#include "avcodec.h"
30#include "dsputil.h"
31#include "get_bits.h"
32
33typedef struct {
34    AVCodecContext *avctx;
35    DSPContext dsp;
36
37    int            size;
38    uint8_t        *val; /* First holds the lengths of vlc symbols and then their values */
39} VBLEContext;
40
41static uint8_t vble_read_reverse_unary(GetBitContext *gb)
42{
43    /* At most we need to read 9 bits total to get indices up to 8 */
44    uint8_t val = show_bits(gb, 8);
45
46    if (val) {
47        val = 7 - av_log2_16bit(av_reverse[val]);
48        skip_bits(gb, val + 1);
49        return val;
50    } else {
51        skip_bits(gb, 8);
52        if (get_bits1(gb))
53            return 8;
54    }
55
56    /* Return something larger than 8 on error */
57    return UINT8_MAX;
58}
59
60static int vble_unpack(VBLEContext *ctx, GetBitContext *gb)
61{
62    int i;
63
64    /* Read all the lengths in first */
65    for (i = 0; i < ctx->size; i++) {
66        ctx->val[i] = vble_read_reverse_unary(gb);
67
68        if (ctx->val[i] == UINT8_MAX)
69            return -1;
70    }
71
72    for (i = 0; i < ctx->size; i++) {
73        /* Check we have enough bits left */
74        if (get_bits_left(gb) < ctx->val[i])
75            return -1;
76
77        /* get_bits can't take a length of 0 */
78        if (ctx->val[i])
79            ctx->val[i] = (1 << ctx->val[i]) + get_bits(gb, ctx->val[i]) - 1;
80    }
81
82    return 0;
83}
84
85static void vble_restore_plane(VBLEContext *ctx, int plane, int offset,
86                              int width, int height)
87{
88    AVFrame *pic = ctx->avctx->coded_frame;
89    uint8_t *dst = pic->data[plane];
90    uint8_t *val = ctx->val + offset;
91    int stride = pic->linesize[plane];
92    int i, j, left, left_top;
93
94    for (i = 0; i < height; i++) {
95        for (j = 0; j < width; j++)
96            val[j] = (val[j] >> 1) ^ -(val[j] & 1);
97
98        if (i) {
99            left = 0;
100            left_top = dst[-stride];
101            ctx->dsp.add_hfyu_median_prediction(dst, dst-stride, val,
102                                                width, &left, &left_top);
103        } else {
104            dst[0] = val[0];
105            for (j = 1; j < width; j++)
106                dst[j] = val[j] + dst[j - 1];
107        }
108        dst += stride;
109        val += width;
110    }
111}
112
113static int vble_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
114                             AVPacket *avpkt)
115{
116    VBLEContext *ctx = avctx->priv_data;
117    AVFrame *pic = avctx->coded_frame;
118    GetBitContext gb;
119    const uint8_t *src = avpkt->data;
120    int version;
121    int offset = 0;
122    int width_uv = avctx->width / 2, height_uv = avctx->height / 2;
123
124    pic->reference = 0;
125
126    /* Clear buffer if need be */
127    if (pic->data[0])
128        avctx->release_buffer(avctx, pic);
129
130    /* Allocate buffer */
131    if (avctx->get_buffer(avctx, pic) < 0) {
132        av_log(avctx, AV_LOG_ERROR, "Could not allocate buffer.\n");
133        return AVERROR(ENOMEM);
134    }
135
136    /* Set flags */
137    pic->key_frame = 1;
138    pic->pict_type = AV_PICTURE_TYPE_I;
139
140    /* Version should always be 1 */
141    version = AV_RL32(src);
142
143    if (version != 1) {
144        av_log(avctx, AV_LOG_ERROR, "Unsupported VBLE Version: %d\n", version);
145        return AVERROR_INVALIDDATA;
146    }
147
148    init_get_bits(&gb, src + 4, (avpkt->size - 4) * 8);
149
150    /* Unpack */
151    if (vble_unpack(ctx, &gb) < 0) {
152        av_log(avctx, AV_LOG_ERROR, "Invalid Code\n");
153        return AVERROR_INVALIDDATA;
154    }
155
156    /* Restore planes. Should be almost identical to Huffyuv's. */
157    vble_restore_plane(ctx, 0, offset, avctx->width, avctx->height);
158
159    /* Chroma */
160    if (!(ctx->avctx->flags & CODEC_FLAG_GRAY)) {
161        offset += avctx->width * avctx->height;
162        vble_restore_plane(ctx, 1, offset, width_uv, height_uv);
163
164        offset += width_uv * height_uv;
165        vble_restore_plane(ctx, 2, offset, width_uv, height_uv);
166    }
167
168    *data_size = sizeof(AVFrame);
169    *(AVFrame *)data = *pic;
170
171    return avpkt->size;
172}
173
174static av_cold int vble_decode_close(AVCodecContext *avctx)
175{
176    VBLEContext *ctx = avctx->priv_data;
177    AVFrame *pic = avctx->coded_frame;
178
179    if (pic->data[0])
180        avctx->release_buffer(avctx, pic);
181
182    av_freep(&avctx->coded_frame);
183    av_freep(&ctx->val);
184
185    return 0;
186}
187
188static av_cold int vble_decode_init(AVCodecContext *avctx)
189{
190    VBLEContext *ctx = avctx->priv_data;
191
192    /* Stash for later use */
193    ctx->avctx = avctx;
194    dsputil_init(&ctx->dsp, avctx);
195
196    avctx->pix_fmt = PIX_FMT_YUV420P;
197    avctx->bits_per_raw_sample = 8;
198    avctx->coded_frame = avcodec_alloc_frame();
199
200    if (!avctx->coded_frame) {
201        av_log(avctx, AV_LOG_ERROR, "Could not allocate frame.\n");
202        return AVERROR(ENOMEM);
203    }
204
205    ctx->size = avpicture_get_size(avctx->pix_fmt,
206                                   avctx->width, avctx->height);
207
208    ctx->val = av_malloc(ctx->size * sizeof(*ctx->val));
209
210    if (!ctx->val) {
211        av_log(avctx, AV_LOG_ERROR, "Could not allocate values buffer.\n");
212        vble_decode_close(avctx);
213        return AVERROR(ENOMEM);
214    }
215
216    return 0;
217}
218
219AVCodec ff_vble_decoder = {
220    .name           = "vble",
221    .type           = AVMEDIA_TYPE_VIDEO,
222    .id             = CODEC_ID_VBLE,
223    .priv_data_size = sizeof(VBLEContext),
224    .init           = vble_decode_init,
225    .close          = vble_decode_close,
226    .decode         = vble_decode_frame,
227    .capabilities   = CODEC_CAP_DR1,
228    .long_name      = NULL_IF_CONFIG_SMALL("VBLE Lossless Codec"),
229};
230