/* * KMVC decoder * Copyright (c) 2006 Konstantin Shishkov * * This file is part of Libav. * * 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. * * 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 Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * Karl Morton's Video Codec decoder */ #include <stdio.h> #include <stdlib.h> #include "avcodec.h" #include "bytestream.h" #define KMVC_KEYFRAME 0x80 #define KMVC_PALETTE 0x40 #define KMVC_METHOD 0x0F /* * Decoder context */ typedef struct KmvcContext { AVCodecContext *avctx; AVFrame pic; int setpal; int palsize; uint32_t pal[256]; uint8_t *cur, *prev; uint8_t *frm0, *frm1; } KmvcContext; typedef struct BitBuf { int bits; int bitbuf; } BitBuf; #define BLK(data, x, y) data[(x) + (y) * 320] #define kmvc_init_getbits(bb, src) bb.bits = 7; bb.bitbuf = *src++; #define kmvc_getbit(bb, src, res) {\ res = 0; \ if (bb.bitbuf & (1 << bb.bits)) res = 1; \ bb.bits--; \ if(bb.bits == -1) { \ bb.bitbuf = *src++; \ bb.bits = 7; \ } \ } static void kmvc_decode_intra_8x8(KmvcContext * ctx, const uint8_t * src, int w, int h) { BitBuf bb; int res, val; int i, j; int bx, by; int l0x, l1x, l0y, l1y; int mx, my; kmvc_init_getbits(bb, src); for (by = 0; by < h; by += 8) for (bx = 0; bx < w; bx += 8) { kmvc_getbit(bb, src, res); if (!res) { // fill whole 8x8 block val = *src++; for (i = 0; i < 64; i++) BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) = val; } else { // handle four 4x4 subblocks for (i = 0; i < 4; i++) { l0x = bx + (i & 1) * 4; l0y = by + (i & 2) * 2; kmvc_getbit(bb, src, res); if (!res) { kmvc_getbit(bb, src, res); if (!res) { // fill whole 4x4 block val = *src++; for (j = 0; j < 16; j++) BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) = val; } else { // copy block from already decoded place val = *src++; mx = val & 0xF; my = val >> 4; for (j = 0; j < 16; j++) BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) = BLK(ctx->cur, l0x + (j & 3) - mx, l0y + (j >> 2) - my); } } else { // descend to 2x2 sub-sub-blocks for (j = 0; j < 4; j++) { l1x = l0x + (j & 1) * 2; l1y = l0y + (j & 2); kmvc_getbit(bb, src, res); if (!res) { kmvc_getbit(bb, src, res); if (!res) { // fill whole 2x2 block val = *src++; BLK(ctx->cur, l1x, l1y) = val; BLK(ctx->cur, l1x + 1, l1y) = val; BLK(ctx->cur, l1x, l1y + 1) = val; BLK(ctx->cur, l1x + 1, l1y + 1) = val; } else { // copy block from already decoded place val = *src++; mx = val & 0xF; my = val >> 4; BLK(ctx->cur, l1x, l1y) = BLK(ctx->cur, l1x - mx, l1y - my); BLK(ctx->cur, l1x + 1, l1y) = BLK(ctx->cur, l1x + 1 - mx, l1y - my); BLK(ctx->cur, l1x, l1y + 1) = BLK(ctx->cur, l1x - mx, l1y + 1 - my); BLK(ctx->cur, l1x + 1, l1y + 1) = BLK(ctx->cur, l1x + 1 - mx, l1y + 1 - my); } } else { // read values for block BLK(ctx->cur, l1x, l1y) = *src++; BLK(ctx->cur, l1x + 1, l1y) = *src++; BLK(ctx->cur, l1x, l1y + 1) = *src++; BLK(ctx->cur, l1x + 1, l1y + 1) = *src++; } } } } } } } static void kmvc_decode_inter_8x8(KmvcContext * ctx, const uint8_t * src, int w, int h) { BitBuf bb; int res, val; int i, j; int bx, by; int l0x, l1x, l0y, l1y; int mx, my; kmvc_init_getbits(bb, src); for (by = 0; by < h; by += 8) for (bx = 0; bx < w; bx += 8) { kmvc_getbit(bb, src, res); if (!res) { kmvc_getbit(bb, src, res); if (!res) { // fill whole 8x8 block val = *src++; for (i = 0; i < 64; i++) BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) = val; } else { // copy block from previous frame for (i = 0; i < 64; i++) BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) = BLK(ctx->prev, bx + (i & 0x7), by + (i >> 3)); } } else { // handle four 4x4 subblocks for (i = 0; i < 4; i++) { l0x = bx + (i & 1) * 4; l0y = by + (i & 2) * 2; kmvc_getbit(bb, src, res); if (!res) { kmvc_getbit(bb, src, res); if (!res) { // fill whole 4x4 block val = *src++; for (j = 0; j < 16; j++) BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) = val; } else { // copy block val = *src++; mx = (val & 0xF) - 8; my = (val >> 4) - 8; for (j = 0; j < 16; j++) BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) = BLK(ctx->prev, l0x + (j & 3) + mx, l0y + (j >> 2) + my); } } else { // descend to 2x2 sub-sub-blocks for (j = 0; j < 4; j++) { l1x = l0x + (j & 1) * 2; l1y = l0y + (j & 2); kmvc_getbit(bb, src, res); if (!res) { kmvc_getbit(bb, src, res); if (!res) { // fill whole 2x2 block val = *src++; BLK(ctx->cur, l1x, l1y) = val; BLK(ctx->cur, l1x + 1, l1y) = val; BLK(ctx->cur, l1x, l1y + 1) = val; BLK(ctx->cur, l1x + 1, l1y + 1) = val; } else { // copy block val = *src++; mx = (val & 0xF) - 8; my = (val >> 4) - 8; BLK(ctx->cur, l1x, l1y) = BLK(ctx->prev, l1x + mx, l1y + my); BLK(ctx->cur, l1x + 1, l1y) = BLK(ctx->prev, l1x + 1 + mx, l1y + my); BLK(ctx->cur, l1x, l1y + 1) = BLK(ctx->prev, l1x + mx, l1y + 1 + my); BLK(ctx->cur, l1x + 1, l1y + 1) = BLK(ctx->prev, l1x + 1 + mx, l1y + 1 + my); } } else { // read values for block BLK(ctx->cur, l1x, l1y) = *src++; BLK(ctx->cur, l1x + 1, l1y) = *src++; BLK(ctx->cur, l1x, l1y + 1) = *src++; BLK(ctx->cur, l1x + 1, l1y + 1) = *src++; } } } } } } } static int decode_frame(AVCodecContext * avctx, void *data, int *data_size, AVPacket *avpkt) { const uint8_t *buf = avpkt->data; int buf_size = avpkt->size; KmvcContext *const ctx = avctx->priv_data; uint8_t *out, *src; int i; int header; int blocksize; const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL); if (ctx->pic.data[0]) avctx->release_buffer(avctx, &ctx->pic); ctx->pic.reference = 1; ctx->pic.buffer_hints = FF_BUFFER_HINTS_VALID; if (avctx->get_buffer(avctx, &ctx->pic) < 0) { av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); return -1; } header = *buf++; /* blocksize 127 is really palette change event */ if (buf[0] == 127) { buf += 3; for (i = 0; i < 127; i++) { ctx->pal[i + (header & 0x81)] = AV_RB24(buf); buf += 4; } buf -= 127 * 4 + 3; } if (header & KMVC_KEYFRAME) { ctx->pic.key_frame = 1; ctx->pic.pict_type = AV_PICTURE_TYPE_I; } else { ctx->pic.key_frame = 0; ctx->pic.pict_type = AV_PICTURE_TYPE_P; } if (header & KMVC_PALETTE) { ctx->pic.palette_has_changed = 1; // palette starts from index 1 and has 127 entries for (i = 1; i <= ctx->palsize; i++) { ctx->pal[i] = bytestream_get_be24(&buf); } } if (pal) { ctx->pic.palette_has_changed = 1; memcpy(ctx->pal, pal, AVPALETTE_SIZE); } if (ctx->setpal) { ctx->setpal = 0; ctx->pic.palette_has_changed = 1; } /* make the palette available on the way out */ memcpy(ctx->pic.data[1], ctx->pal, 1024); blocksize = *buf++; if (blocksize != 8 && blocksize != 127) { av_log(avctx, AV_LOG_ERROR, "Block size = %i\n", blocksize); return -1; } memset(ctx->cur, 0, 320 * 200); switch (header & KMVC_METHOD) { case 0: case 1: // used in palette changed event memcpy(ctx->cur, ctx->prev, 320 * 200); break; case 3: kmvc_decode_intra_8x8(ctx, buf, avctx->width, avctx->height); break; case 4: kmvc_decode_inter_8x8(ctx, buf, avctx->width, avctx->height); break; default: av_log(avctx, AV_LOG_ERROR, "Unknown compression method %i\n", header & KMVC_METHOD); return -1; } out = ctx->pic.data[0]; src = ctx->cur; for (i = 0; i < avctx->height; i++) { memcpy(out, src, avctx->width); src += 320; out += ctx->pic.linesize[0]; } /* flip buffers */ if (ctx->cur == ctx->frm0) { ctx->cur = ctx->frm1; ctx->prev = ctx->frm0; } else { ctx->cur = ctx->frm0; ctx->prev = ctx->frm1; } *data_size = sizeof(AVFrame); *(AVFrame *) data = ctx->pic; /* always report that the buffer was completely consumed */ return buf_size; } /* * Init kmvc decoder */ static av_cold int decode_init(AVCodecContext * avctx) { KmvcContext *const c = avctx->priv_data; int i; c->avctx = avctx; if (avctx->width > 320 || avctx->height > 200) { av_log(avctx, AV_LOG_ERROR, "KMVC supports frames <= 320x200\n"); return -1; } c->frm0 = av_mallocz(320 * 200); c->frm1 = av_mallocz(320 * 200); c->cur = c->frm0; c->prev = c->frm1; for (i = 0; i < 256; i++) { c->pal[i] = i * 0x10101; } if (avctx->extradata_size < 12) { av_log(NULL, 0, "Extradata missing, decoding may not work properly...\n"); c->palsize = 127; } else { c->palsize = AV_RL16(avctx->extradata + 10); } if (avctx->extradata_size == 1036) { // palette in extradata uint8_t *src = avctx->extradata + 12; for (i = 0; i < 256; i++) { c->pal[i] = AV_RL32(src); src += 4; } c->setpal = 1; } avctx->pix_fmt = PIX_FMT_PAL8; return 0; } /* * Uninit kmvc decoder */ static av_cold int decode_end(AVCodecContext * avctx) { KmvcContext *const c = avctx->priv_data; av_freep(&c->frm0); av_freep(&c->frm1); if (c->pic.data[0]) avctx->release_buffer(avctx, &c->pic); return 0; } AVCodec ff_kmvc_decoder = { "kmvc", AVMEDIA_TYPE_VIDEO, CODEC_ID_KMVC, sizeof(KmvcContext), decode_init, NULL, decode_end, decode_frame, CODEC_CAP_DR1, .long_name = NULL_IF_CONFIG_SMALL("Karl Morton's video codec"), };