X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavcodec%2Fxan.c;h=876a9a5558bccf6071cd5cc93d3daf4e5b26a268;hb=44f566b79afcbbb152ec21db667ea3d2f42e8f8d;hp=d75d4692a2bd6dc786c421e770fa4a648a2325bd;hpb=72415b2adb2c25f95ceede49001bb97ed9247dbb;p=ffmpeg diff --git a/libavcodec/xan.c b/libavcodec/xan.c index d75d4692a2b..876a9a5558b 100644 --- a/libavcodec/xan.c +++ b/libavcodec/xan.c @@ -2,25 +2,25 @@ * 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) @@ -40,6 +40,15 @@ // 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; @@ -55,6 +64,10 @@ typedef struct XanContext { unsigned char *buffer2; int buffer2_size; + unsigned *palettes; + int palettes_count; + int cur_palette; + int frame_size; } XanContext; @@ -66,23 +79,17 @@ static av_cold int xan_decode_init(AVCodecContext *avctx) 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; s->buffer1_size = avctx->width * avctx->height; s->buffer1 = av_malloc(s->buffer1_size); if (!s->buffer1) - return -1; + return AVERROR(ENOMEM); s->buffer2_size = avctx->width * avctx->height; s->buffer2 = av_malloc(s->buffer2_size + 130); if (!s->buffer2) { av_freep(&s->buffer1); - return -1; + return AVERROR(ENOMEM); } return 0; @@ -351,39 +358,166 @@ static void xan_wc3_decode_frame(XanContext *s) { } } -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]) @@ -411,11 +545,12 @@ static av_cold int xan_decode_end(AVCodecContext *avctx) 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", AVMEDIA_TYPE_VIDEO, CODEC_ID_XAN_WC3, @@ -428,17 +563,3 @@ AVCodec xan_wc3_decoder = { .long_name = NULL_IF_CONFIG_SMALL("Wing Commander III / Xan"), }; -/* -AVCodec xan_wc4_decoder = { - "xan_wc4", - AVMEDIA_TYPE_VIDEO, - CODEC_ID_XAN_WC4, - sizeof(XanContext), - xan_decode_init, - NULL, - xan_decode_end, - xan_decode_frame, - CODEC_CAP_DR1, - .long_name = NULL_IF_CONFIG_SMALL("Wing Commander IV / Xxan"), -}; -*/