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tmv.c
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1 /*
2  * 8088flex TMV video decoder
3  * Copyright (c) 2009 Daniel Verkamp <daniel at drv.nu>
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  * 8088flex TMV video decoder
25  * @author Daniel Verkamp
26  * @see http://www.oldskool.org/pc/8088_Corruption
27  */
28 
29 #include <string.h>
30 
31 #include "avcodec.h"
32 #include "internal.h"
33 #include "libavutil/internal.h"
35 
36 #include "cga_data.h"
37 
38 static int tmv_decode_frame(AVCodecContext *avctx, void *data,
39  int *got_frame, AVPacket *avpkt)
40 {
41  AVFrame *frame = data;
42  const uint8_t *src = avpkt->data;
43  uint8_t *dst;
44  unsigned char_cols = avctx->width >> 3;
45  unsigned char_rows = avctx->height >> 3;
46  unsigned x, y, fg, bg, c;
47  int ret;
48 
49  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
50  return ret;
51 
52  if (avpkt->size < 2*char_rows*char_cols) {
53  av_log(avctx, AV_LOG_ERROR,
54  "Input buffer too small, truncated sample?\n");
55  *got_frame = 0;
56  return AVERROR_INVALIDDATA;
57  }
58 
60  frame->key_frame = 1;
61  dst = frame->data[0];
62 
63  frame->palette_has_changed = 1;
64  memcpy(frame->data[1], ff_cga_palette, 16 * 4);
65  memset(frame->data[1] + 16 * 4, 0, AVPALETTE_SIZE - 16 * 4);
66 
67  for (y = 0; y < char_rows; y++) {
68  for (x = 0; x < char_cols; x++) {
69  c = *src++;
70  bg = *src >> 4;
71  fg = *src++ & 0xF;
72  ff_draw_pc_font(dst + x * 8, frame->linesize[0],
73  avpriv_cga_font, 8, c, fg, bg);
74  }
75  dst += frame->linesize[0] * 8;
76  }
77 
78  *got_frame = 1;
79 
80  return avpkt->size;
81 }
82 
84 {
85  avctx->pix_fmt = AV_PIX_FMT_PAL8;
86  return 0;
87 }
88 
90  .name = "tmv",
91  .long_name = NULL_IF_CONFIG_SMALL("8088flex TMV"),
92  .type = AVMEDIA_TYPE_VIDEO,
93  .id = AV_CODEC_ID_TMV,
94  .init = tmv_decode_init,
95  .decode = tmv_decode_frame,
96  .capabilities = AV_CODEC_CAP_DR1,
97 };
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
This structure describes decoded (raw) audio or video data.
Definition: frame.h:184
ptrdiff_t const GLvoid * data
Definition: opengl_enc.c:101
int size
Definition: avcodec.h:1601
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:1903
AVCodec.
Definition: avcodec.h:3589
uint8_t
#define av_cold
Definition: attributes.h:82
8 bits with AV_PIX_FMT_RGB32 palette
Definition: pixfmt.h:73
#define AVPALETTE_SIZE
Definition: pixfmt.h:32
static AVFrame * frame
uint8_t * data
Definition: avcodec.h:1600
CGA/EGA/VGA ROM data.
#define av_log(a,...)
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
const uint8_t avpriv_cga_font[2048]
Definition: xga_font_data.c:29
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:176
static int tmv_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: tmv.c:38
const char * name
Name of the codec implementation.
Definition: avcodec.h:3596
common internal API header
AVCodec ff_tmv_decoder
Definition: tmv.c:89
enum AVPictureType pict_type
Picture type of the frame.
Definition: frame.h:258
int width
picture width / height.
Definition: avcodec.h:1862
#define src
Definition: vp9dsp.c:530
void ff_draw_pc_font(uint8_t *dst, int linesize, const uint8_t *font, int font_height, int ch, int fg, int bg)
Draw CGA/EGA/VGA font to 8-bit pixel buffer.
Definition: cga_data.c:46
Libavcodec external API header.
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:215
main external API structure.
Definition: avcodec.h:1675
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: utils.c:934
int palette_has_changed
Tell user application that palette has changed from previous frame.
Definition: frame.h:328
const uint32_t ff_cga_palette[16]
Definition: cga_data.c:30
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:198
common internal api header.
static double c[64]
int key_frame
1 -> keyframe, 0-> not
Definition: frame.h:253
This structure stores compressed data.
Definition: avcodec.h:1577
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:958
CGA/EGA/VGA ROM font data.
static av_cold int tmv_decode_init(AVCodecContext *avctx)
Definition: tmv.c:83