* Wing Commander/Xan Video Decoder
* Copyright (C) 2003 the ffmpeg project
*
- * This file is part of FFmpeg.
+ * This file is part of Libav.
*
- * FFmpeg is free software; you can redistribute it and/or
+ * 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.
*
- * FFmpeg is distributed in the hope that it will be useful,
+ * 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 FFmpeg; if not, write to the Free Software
+ * License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
- * @file libavcodec/xan.c
+ * @file
* Xan video decoder for Wing Commander III computer game
* by Mario Brito (mbrito@student.dei.uc.pt)
* and Mike Melanson (melanson@pcisys.net)
// for av_memcpy_backptr
#include "libavutil/lzo.h"
+#define RUNTIME_GAMMA 0
+
+#define VGA__TAG MKTAG('V', 'G', 'A', ' ')
+#define PALT_TAG MKTAG('P', 'A', 'L', 'T')
+#define SHOT_TAG MKTAG('S', 'H', 'O', 'T')
+#define PALETTE_COUNT 256
+#define PALETTE_SIZE (PALETTE_COUNT * 3)
+#define PALETTES_MAX 256
+
typedef struct XanContext {
AVCodecContext *avctx;
unsigned char *buffer2;
int buffer2_size;
+ unsigned *palettes;
+ int palettes_count;
+ int cur_palette;
+
int frame_size;
} XanContext;
s->avctx = avctx;
s->frame_size = 0;
- if ((avctx->codec->id == CODEC_ID_XAN_WC3) &&
- (s->avctx->palctrl == NULL)) {
- av_log(avctx, AV_LOG_ERROR, " WC3 Xan video: palette expected.\n");
- return -1;
- }
-
avctx->pix_fmt = PIX_FMT_PAL8;
- if(avcodec_check_dimensions(avctx, avctx->width, avctx->height))
- return -1;
-
s->buffer1_size = avctx->width * avctx->height;
s->buffer1 = av_malloc(s->buffer1_size);
+ if (!s->buffer1)
+ return AVERROR(ENOMEM);
s->buffer2_size = avctx->width * avctx->height;
s->buffer2 = av_malloc(s->buffer2_size + 130);
- if (!s->buffer1 || !s->buffer2)
- return -1;
+ if (!s->buffer2) {
+ av_freep(&s->buffer1);
+ return AVERROR(ENOMEM);
+ }
return 0;
}
line_inc = stride - width;
index = y * stride + x;
current_x = x;
- while((pixel_count--) && (index < s->frame_size)) {
-
- /* don't do a memcpy() here; keyframes generally copy an entire
- * frame of data and the stride needs to be accounted for */
- palette_plane[index++] = *pixel_buffer++;
+ while(pixel_count && (index < s->frame_size)) {
+ int count = FFMIN(pixel_count, width - current_x);
+ memcpy(palette_plane + index, pixel_buffer, count);
+ pixel_count -= count;
+ index += count;
+ pixel_buffer += count;
+ current_x += count;
- current_x++;
if (current_x >= width) {
index += line_inc;
current_x = 0;
curframe_x = x;
prevframe_index = (y + motion_y) * stride + x + motion_x;
prevframe_x = x + motion_x;
- while((pixel_count--) && (curframe_index < s->frame_size)) {
+ while(pixel_count && (curframe_index < s->frame_size)) {
+ int count = FFMIN3(pixel_count, width - curframe_x, width - prevframe_x);
- palette_plane[curframe_index++] =
- prev_palette_plane[prevframe_index++];
+ memcpy(palette_plane + curframe_index, prev_palette_plane + prevframe_index, count);
+ pixel_count -= count;
+ curframe_index += count;
+ prevframe_index += count;
+ curframe_x += count;
+ prevframe_x += count;
- curframe_x++;
if (curframe_x >= width) {
curframe_index += line_inc;
curframe_x = 0;
}
- prevframe_x++;
if (prevframe_x >= width) {
prevframe_index += line_inc;
prevframe_x = 0;
}
}
-static void xan_wc4_decode_frame(XanContext *s) {
+#if RUNTIME_GAMMA
+static inline unsigned mul(unsigned a, unsigned b)
+{
+ return (a * b) >> 16;
+}
+
+static inline unsigned pow4(unsigned a)
+{
+ unsigned square = mul(a, a);
+ return mul(square, square);
+}
+
+static inline unsigned pow5(unsigned a)
+{
+ return mul(pow4(a), a);
+}
+
+static uint8_t gamma_corr(uint8_t in) {
+ unsigned lo, hi = 0xff40, target;
+ int i = 15;
+ in = (in << 2) | (in >> 6);
+ /* equivalent float code:
+ if (in >= 252)
+ return 253;
+ return round(pow(in / 256.0, 0.8) * 256);
+ */
+ lo = target = in << 8;
+ do {
+ unsigned mid = (lo + hi) >> 1;
+ unsigned pow = pow5(mid);
+ if (pow > target) hi = mid;
+ else lo = mid;
+ } while (--i);
+ return (pow4((lo + hi) >> 1) + 0x80) >> 8;
}
+#else
+/**
+ * This is a gamma correction that xan3 applies to all palette entries.
+ *
+ * There is a peculiarity, namely that the values are clamped to 253 -
+ * it seems likely that this table was calculated by a buggy fixed-point
+ * implementation, the one above under RUNTIME_GAMMA behaves like this for
+ * example.
+ * The exponent value of 0.8 can be explained by this as well, since 0.8 = 4/5
+ * and thus pow(x, 0.8) is still easy to calculate.
+ * Also, the input values are first rotated to the left by 2.
+ */
+static const uint8_t gamma_lookup[256] = {
+ 0x00, 0x09, 0x10, 0x16, 0x1C, 0x21, 0x27, 0x2C,
+ 0x31, 0x35, 0x3A, 0x3F, 0x43, 0x48, 0x4C, 0x50,
+ 0x54, 0x59, 0x5D, 0x61, 0x65, 0x69, 0x6D, 0x71,
+ 0x75, 0x79, 0x7D, 0x80, 0x84, 0x88, 0x8C, 0x8F,
+ 0x93, 0x97, 0x9A, 0x9E, 0xA2, 0xA5, 0xA9, 0xAC,
+ 0xB0, 0xB3, 0xB7, 0xBA, 0xBE, 0xC1, 0xC5, 0xC8,
+ 0xCB, 0xCF, 0xD2, 0xD5, 0xD9, 0xDC, 0xDF, 0xE3,
+ 0xE6, 0xE9, 0xED, 0xF0, 0xF3, 0xF6, 0xFA, 0xFD,
+ 0x03, 0x0B, 0x12, 0x18, 0x1D, 0x23, 0x28, 0x2D,
+ 0x32, 0x36, 0x3B, 0x40, 0x44, 0x49, 0x4D, 0x51,
+ 0x56, 0x5A, 0x5E, 0x62, 0x66, 0x6A, 0x6E, 0x72,
+ 0x76, 0x7A, 0x7D, 0x81, 0x85, 0x89, 0x8D, 0x90,
+ 0x94, 0x98, 0x9B, 0x9F, 0xA2, 0xA6, 0xAA, 0xAD,
+ 0xB1, 0xB4, 0xB8, 0xBB, 0xBF, 0xC2, 0xC5, 0xC9,
+ 0xCC, 0xD0, 0xD3, 0xD6, 0xDA, 0xDD, 0xE0, 0xE4,
+ 0xE7, 0xEA, 0xED, 0xF1, 0xF4, 0xF7, 0xFA, 0xFD,
+ 0x05, 0x0D, 0x13, 0x19, 0x1F, 0x24, 0x29, 0x2E,
+ 0x33, 0x38, 0x3C, 0x41, 0x45, 0x4A, 0x4E, 0x52,
+ 0x57, 0x5B, 0x5F, 0x63, 0x67, 0x6B, 0x6F, 0x73,
+ 0x77, 0x7B, 0x7E, 0x82, 0x86, 0x8A, 0x8D, 0x91,
+ 0x95, 0x99, 0x9C, 0xA0, 0xA3, 0xA7, 0xAA, 0xAE,
+ 0xB2, 0xB5, 0xB9, 0xBC, 0xBF, 0xC3, 0xC6, 0xCA,
+ 0xCD, 0xD0, 0xD4, 0xD7, 0xDA, 0xDE, 0xE1, 0xE4,
+ 0xE8, 0xEB, 0xEE, 0xF1, 0xF5, 0xF8, 0xFB, 0xFD,
+ 0x07, 0x0E, 0x15, 0x1A, 0x20, 0x25, 0x2A, 0x2F,
+ 0x34, 0x39, 0x3D, 0x42, 0x46, 0x4B, 0x4F, 0x53,
+ 0x58, 0x5C, 0x60, 0x64, 0x68, 0x6C, 0x70, 0x74,
+ 0x78, 0x7C, 0x7F, 0x83, 0x87, 0x8B, 0x8E, 0x92,
+ 0x96, 0x99, 0x9D, 0xA1, 0xA4, 0xA8, 0xAB, 0xAF,
+ 0xB2, 0xB6, 0xB9, 0xBD, 0xC0, 0xC4, 0xC7, 0xCB,
+ 0xCE, 0xD1, 0xD5, 0xD8, 0xDB, 0xDF, 0xE2, 0xE5,
+ 0xE9, 0xEC, 0xEF, 0xF2, 0xF6, 0xF9, 0xFC, 0xFD
+};
+#endif
static int xan_decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
- int buf_size = avpkt->size;
+ int ret, buf_size = avpkt->size;
XanContext *s = avctx->priv_data;
- AVPaletteControl *palette_control = avctx->palctrl;
- if (avctx->get_buffer(avctx, &s->current_frame)) {
- av_log(s->avctx, AV_LOG_ERROR, " Xan Video: get_buffer() failed\n");
- return -1;
+ if (avctx->codec->id == CODEC_ID_XAN_WC3) {
+ const uint8_t *buf_end = buf + buf_size;
+ int tag = 0;
+ while (buf_end - buf > 8 && tag != VGA__TAG) {
+ unsigned *tmpptr;
+ uint32_t new_pal;
+ int size;
+ int i;
+ tag = bytestream_get_le32(&buf);
+ size = bytestream_get_be32(&buf);
+ size = FFMIN(size, buf_end - buf);
+ switch (tag) {
+ case PALT_TAG:
+ if (size < PALETTE_SIZE)
+ return AVERROR_INVALIDDATA;
+ if (s->palettes_count >= PALETTES_MAX)
+ return AVERROR_INVALIDDATA;
+ tmpptr = av_realloc(s->palettes, (s->palettes_count + 1) * AVPALETTE_SIZE);
+ if (!tmpptr)
+ return AVERROR(ENOMEM);
+ s->palettes = tmpptr;
+ tmpptr += s->palettes_count * AVPALETTE_COUNT;
+ for (i = 0; i < PALETTE_COUNT; i++) {
+#if RUNTIME_GAMMA
+ int r = gamma_corr(*buf++);
+ int g = gamma_corr(*buf++);
+ int b = gamma_corr(*buf++);
+#else
+ int r = gamma_lookup[*buf++];
+ int g = gamma_lookup[*buf++];
+ int b = gamma_lookup[*buf++];
+#endif
+ *tmpptr++ = (r << 16) | (g << 8) | b;
+ }
+ s->palettes_count++;
+ break;
+ case SHOT_TAG:
+ if (size < 4)
+ return AVERROR_INVALIDDATA;
+ new_pal = bytestream_get_le32(&buf);
+ if (new_pal < s->palettes_count) {
+ s->cur_palette = new_pal;
+ } else
+ av_log(avctx, AV_LOG_ERROR, "Invalid palette selected\n");
+ break;
+ case VGA__TAG:
+ break;
+ default:
+ buf += size;
+ break;
+ }
+ }
+ buf_size = buf_end - buf;
+ }
+ if ((ret = avctx->get_buffer(avctx, &s->current_frame))) {
+ av_log(s->avctx, AV_LOG_ERROR, "get_buffer() failed\n");
+ return ret;
}
s->current_frame.reference = 3;
if (!s->frame_size)
s->frame_size = s->current_frame.linesize[0] * s->avctx->height;
- palette_control->palette_changed = 0;
- memcpy(s->current_frame.data[1], palette_control->palette,
- AVPALETTE_SIZE);
- s->current_frame.palette_has_changed = 1;
+ memcpy(s->current_frame.data[1], s->palettes + s->cur_palette * AVPALETTE_COUNT, AVPALETTE_SIZE);
s->buf = buf;
s->size = buf_size;
- if (avctx->codec->id == CODEC_ID_XAN_WC3)
- xan_wc3_decode_frame(s);
- else if (avctx->codec->id == CODEC_ID_XAN_WC4)
- xan_wc4_decode_frame(s);
+ xan_wc3_decode_frame(s);
/* release the last frame if it is allocated */
if (s->last_frame.data[0])
if (s->current_frame.data[0])
avctx->release_buffer(avctx, &s->current_frame);
- av_free(s->buffer1);
- av_free(s->buffer2);
+ av_freep(&s->buffer1);
+ av_freep(&s->buffer2);
+ av_freep(&s->palettes);
return 0;
}
-AVCodec xan_wc3_decoder = {
+AVCodec ff_xan_wc3_decoder = {
"xan_wc3",
- CODEC_TYPE_VIDEO,
+ AVMEDIA_TYPE_VIDEO,
CODEC_ID_XAN_WC3,
sizeof(XanContext),
xan_decode_init,
.long_name = NULL_IF_CONFIG_SMALL("Wing Commander III / Xan"),
};
-/*
-AVCodec xan_wc4_decoder = {
- "xan_wc4",
- CODEC_TYPE_VIDEO,
- CODEC_ID_XAN_WC4,
- sizeof(XanContext),
- xan_decode_init,
- NULL,
- xan_decode_end,
- xan_decode_frame,
- CODEC_CAP_DR1,
-};
-*/
projects / ffmpeg / blobdiff