[deb_ffmpeg.git] / ffmpeg / libavcodec / mss1.c

/*
 * Microsoft Screen 1 (aka Windows Media Video V7 Screen) decoder
 * Copyright (c) 2012 Konstantin Shishkov
 *
 * 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
 * Microsoft Screen 1 (aka Windows Media Video V7 Screen) decoder
 */

#include "avcodec.h"
#include "internal.h"
#include "mss12.h"

typedef struct MSS1Context {
    MSS12Context   ctx;
    AVFrame       *pic;
    SliceContext   sc;
} MSS1Context;

static void arith_normalise(ArithCoder *c)
{
    for (;;) {
        if (c->high >= 0x8000) {
            if (c->low < 0x8000) {
                if (c->low >= 0x4000 && c->high < 0xC000) {
                    c->value -= 0x4000;
                    c->low   -= 0x4000;
                    c->high  -= 0x4000;
                } else {
                    return;
                }
            } else {
                c->value -= 0x8000;
                c->low   -= 0x8000;
                c->high  -= 0x8000;
            }
        }
        c->value <<= 1;
        c->low   <<= 1;
        c->high  <<= 1;
        c->high   |= 1;
        c->value  |= get_bits1(c->gbc.gb);
    }
}

ARITH_GET_BIT(arith)

static int arith_get_bits(ArithCoder *c, int bits)
{
    int range = c->high - c->low + 1;
    int val   = (((c->value - c->low + 1) << bits) - 1) / range;
    int prob  = range * val;

    c->high   = ((prob + range) >> bits) + c->low - 1;
    c->low   += prob >> bits;

    arith_normalise(c);

    return val;
}

static int arith_get_number(ArithCoder *c, int mod_val)
{
    int range = c->high - c->low + 1;
    int val   = ((c->value - c->low + 1) * mod_val - 1) / range;
    int prob  = range * val;

    c->high   = (prob + range) / mod_val + c->low - 1;
    c->low   += prob / mod_val;

    arith_normalise(c);

    return val;
}

static int arith_get_prob(ArithCoder *c, int16_t *probs)
{
    int range = c->high - c->low + 1;
    int val   = ((c->value - c->low + 1) * probs[0] - 1) / range;
    int sym   = 1;

    while (probs[sym] > val)
        sym++;

    c->high = range * probs[sym - 1] / probs[0] + c->low - 1;
    c->low += range * probs[sym]     / probs[0];

    return sym;
}

ARITH_GET_MODEL_SYM(arith)

static void arith_init(ArithCoder *c, GetBitContext *gb)
{
    c->low           = 0;
    c->high          = 0xFFFF;
    c->value         = get_bits(gb, 16);
    c->gbc.gb        = gb;
    c->get_model_sym = arith_get_model_sym;
    c->get_number    = arith_get_number;
}

static int decode_pal(MSS12Context *ctx, ArithCoder *acoder)
{
    int i, ncol, r, g, b;
    uint32_t *pal = ctx->pal + 256 - ctx->free_colours;

    if (!ctx->free_colours)
        return 0;

    ncol = arith_get_number(acoder, ctx->free_colours + 1);
    for (i = 0; i < ncol; i++) {
        r = arith_get_bits(acoder, 8);
        g = arith_get_bits(acoder, 8);
        b = arith_get_bits(acoder, 8);
        *pal++ = (0xFFU << 24) | (r << 16) | (g << 8) | b;
    }

    return !!ncol;
}

static int mss1_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
                             AVPacket *avpkt)
{
    MSS1Context *ctx = avctx->priv_data;
    MSS12Context *c = &ctx->ctx;
    GetBitContext gb;
    ArithCoder acoder;
    int pal_changed = 0;
    int ret;

    if ((ret = init_get_bits8(&gb, avpkt->data, avpkt->size)) < 0)
        return ret;

    arith_init(&acoder, &gb);

    if ((ret = ff_reget_buffer(avctx, ctx->pic)) < 0)
        return ret;

    c->pal_pic    =  ctx->pic->data[0] + ctx->pic->linesize[0] * (avctx->height - 1);
    c->pal_stride = -ctx->pic->linesize[0];
    c->keyframe   = !arith_get_bit(&acoder);
    if (c->keyframe) {
        c->corrupted = 0;
        ff_mss12_slicecontext_reset(&ctx->sc);
        pal_changed        = decode_pal(c, &acoder);
        ctx->pic->key_frame = 1;
        ctx->pic->pict_type = AV_PICTURE_TYPE_I;
    } else {
        if (c->corrupted)
            return AVERROR_INVALIDDATA;
        ctx->pic->key_frame = 0;
        ctx->pic->pict_type = AV_PICTURE_TYPE_P;
    }
    c->corrupted = ff_mss12_decode_rect(&ctx->sc, &acoder, 0, 0,
                                        avctx->width, avctx->height);
    if (c->corrupted)
        return AVERROR_INVALIDDATA;
    memcpy(ctx->pic->data[1], c->pal, AVPALETTE_SIZE);
    ctx->pic->palette_has_changed = pal_changed;

    if ((ret = av_frame_ref(data, ctx->pic)) < 0)
        return ret;

    *got_frame      = 1;

    /* always report that the buffer was completely consumed */
    return avpkt->size;
}

static av_cold int mss1_decode_init(AVCodecContext *avctx)
{
    MSS1Context * const c = avctx->priv_data;
    int ret;

    c->ctx.avctx       = avctx;

    c->pic = av_frame_alloc();
    if (!c->pic)
        return AVERROR(ENOMEM);

    ret = ff_mss12_decode_init(&c->ctx, 0, &c->sc, NULL);
    if (ret < 0)
        av_frame_free(&c->pic);

    avctx->pix_fmt = AV_PIX_FMT_PAL8;

    return ret;
}

static av_cold int mss1_decode_end(AVCodecContext *avctx)
{
    MSS1Context * const ctx = avctx->priv_data;

    av_frame_free(&ctx->pic);
    ff_mss12_decode_end(&ctx->ctx);

    return 0;
}

AVCodec ff_mss1_decoder = {
    .name           = "mss1",
    .long_name      = NULL_IF_CONFIG_SMALL("MS Screen 1"),
    .type           = AVMEDIA_TYPE_VIDEO,
    .id             = AV_CODEC_ID_MSS1,
    .priv_data_size = sizeof(MSS1Context),
    .init           = mss1_decode_init,
    .close          = mss1_decode_end,
    .decode         = mss1_decode_frame,
    .capabilities   = CODEC_CAP_DR1,
};
Commit	Line	Data
2ba45a60 DM	1	/*
	2	* Microsoft Screen 1 (aka Windows Media Video V7 Screen) decoder
	3	* Copyright (c) 2012 Konstantin Shishkov
	4	*
	5	* This file is part of FFmpeg.
	6	*
	7	* FFmpeg 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	* FFmpeg 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 FFmpeg; 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	* Microsoft Screen 1 (aka Windows Media Video V7 Screen) decoder
	25	*/
	26
	27	#include "avcodec.h"
	28	#include "internal.h"
	29	#include "mss12.h"
	30
	31	typedef struct MSS1Context {
	32	MSS12Context ctx;
	33	AVFrame *pic;
	34	SliceContext sc;
	35	} MSS1Context;
	36
	37	static void arith_normalise(ArithCoder *c)
	38	{
	39	for (;;) {
	40	if (c->high >= 0x8000) {
	41	if (c->low < 0x8000) {
	42	if (c->low >= 0x4000 && c->high < 0xC000) {
	43	c->value -= 0x4000;
	44	c->low -= 0x4000;
	45	c->high -= 0x4000;
	46	} else {
	47	return;
	48	}
	49	} else {
	50	c->value -= 0x8000;
	51	c->low -= 0x8000;
	52	c->high -= 0x8000;
	53	}
	54	}
	55	c->value <<= 1;
	56	c->low <<= 1;
	57	c->high <<= 1;
	58	c->high \|= 1;
	59	c->value \|= get_bits1(c->gbc.gb);
	60	}
	61	}
	62
	63	ARITH_GET_BIT(arith)
	64
65	static int arith_get_bits(ArithCoder *c, int bits)
66	{
67	int range = c->high - c->low + 1;
68	int val = (((c->value - c->low + 1) << bits) - 1) / range;
69	int prob = range * val;
70
71	c->high = ((prob + range) >> bits) + c->low - 1;
72	c->low += prob >> bits;
73
74	arith_normalise(c);
75
76	return val;
77	}
78
79	static int arith_get_number(ArithCoder *c, int mod_val)
80	{
81	int range = c->high - c->low + 1;
82	int val = ((c->value - c->low + 1) * mod_val - 1) / range;
83	int prob = range * val;
84
85	c->high = (prob + range) / mod_val + c->low - 1;
86	c->low += prob / mod_val;
87
88	arith_normalise(c);
89
90	return val;
91	}
92
93	static int arith_get_prob(ArithCoder c, int16_t probs)
94	{
95	int range = c->high - c->low + 1;
96	int val = ((c->value - c->low + 1) * probs[0] - 1) / range;
97	int sym = 1;
98
99	while (probs[sym] > val)
100	sym++;
101
102	c->high = range * probs[sym - 1] / probs[0] + c->low - 1;
103	c->low += range * probs[sym] / probs[0];
104
105	return sym;
106	}
107
108	ARITH_GET_MODEL_SYM(arith)
109
110	static void arith_init(ArithCoder c, GetBitContext gb)
111	{
112	c->low = 0;
113	c->high = 0xFFFF;
114	c->value = get_bits(gb, 16);
115	c->gbc.gb = gb;
116	c->get_model_sym = arith_get_model_sym;
117	c->get_number = arith_get_number;
118	}
119
120	static int decode_pal(MSS12Context ctx, ArithCoder acoder)
121	{
122	int i, ncol, r, g, b;
123	uint32_t *pal = ctx->pal + 256 - ctx->free_colours;
124
125	if (!ctx->free_colours)
126	return 0;
127
128	ncol = arith_get_number(acoder, ctx->free_colours + 1);
129	for (i = 0; i < ncol; i++) {
130	r = arith_get_bits(acoder, 8);
131	g = arith_get_bits(acoder, 8);
132	b = arith_get_bits(acoder, 8);
133	*pal++ = (0xFFU << 24) \| (r << 16) \| (g << 8) \| b;
134	}
135
136	return !!ncol;
137	}
138
139	static int mss1_decode_frame(AVCodecContext avctx, void data, int *got_frame,
140	AVPacket *avpkt)
141	{
142	MSS1Context *ctx = avctx->priv_data;
143	MSS12Context *c = &ctx->ctx;
144	GetBitContext gb;
145	ArithCoder acoder;
146	int pal_changed = 0;
147	int ret;
148
149	if ((ret = init_get_bits8(&gb, avpkt->data, avpkt->size)) < 0)
150	return ret;
151
152	arith_init(&acoder, &gb);
153
154	if ((ret = ff_reget_buffer(avctx, ctx->pic)) < 0)
155	return ret;
156
157	c->pal_pic = ctx->pic->data[0] + ctx->pic->linesize[0] * (avctx->height - 1);
158	c->pal_stride = -ctx->pic->linesize[0];
159	c->keyframe = !arith_get_bit(&acoder);
160	if (c->keyframe) {
161	c->corrupted = 0;
162	ff_mss12_slicecontext_reset(&ctx->sc);
163	pal_changed = decode_pal(c, &acoder);
164	ctx->pic->key_frame = 1;
165	ctx->pic->pict_type = AV_PICTURE_TYPE_I;
166	} else {
167	if (c->corrupted)
168	return AVERROR_INVALIDDATA;
169	ctx->pic->key_frame = 0;
170	ctx->pic->pict_type = AV_PICTURE_TYPE_P;
171	}
172	c->corrupted = ff_mss12_decode_rect(&ctx->sc, &acoder, 0, 0,
173	avctx->width, avctx->height);
174	if (c->corrupted)
175	return AVERROR_INVALIDDATA;
176	memcpy(ctx->pic->data[1], c->pal, AVPALETTE_SIZE);
177	ctx->pic->palette_has_changed = pal_changed;
178
179	if ((ret = av_frame_ref(data, ctx->pic)) < 0)
180	return ret;
181
182	*got_frame = 1;
183
184	/* always report that the buffer was completely consumed */
185	return avpkt->size;
186	}
187
188	static av_cold int mss1_decode_init(AVCodecContext *avctx)
189	{
190	MSS1Context * const c = avctx->priv_data;
191	int ret;
192
193	c->ctx.avctx = avctx;
194
195	c->pic = av_frame_alloc();
196	if (!c->pic)
197	return AVERROR(ENOMEM);
198
199	ret = ff_mss12_decode_init(&c->ctx, 0, &c->sc, NULL);
f6fa7814 DM	200	if (ret < 0)
f6fa7814 DM	201	av_frame_free(&c->pic);
2ba45a60 DM	202
	203	avctx->pix_fmt = AV_PIX_FMT_PAL8;
	204
	205	return ret;
	206	}
	207
	208	static av_cold int mss1_decode_end(AVCodecContext *avctx)
	209	{
	210	MSS1Context * const ctx = avctx->priv_data;
	211
	212	av_frame_free(&ctx->pic);
	213	ff_mss12_decode_end(&ctx->ctx);
	214
	215	return 0;
	216	}
	217
	218	AVCodec ff_mss1_decoder = {
	219	.name = "mss1",
	220	.long_name = NULL_IF_CONFIG_SMALL("MS Screen 1"),
	221	.type = AVMEDIA_TYPE_VIDEO,
	222	.id = AV_CODEC_ID_MSS1,
	223	.priv_data_size = sizeof(MSS1Context),
	224	.init = mss1_decode_init,
	225	.close = mss1_decode_end,
	226	.decode = mss1_decode_frame,
	227	.capabilities = CODEC_CAP_DR1,
	228	};