FFmpeg
vcr1.c
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1 /*
2  * ATI VCR1 codec
3  * Copyright (c) 2003 Michael Niedermayer
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  * ATI VCR1 codec
25  */
26 
27 #include "avcodec.h"
28 #include "internal.h"
29 #include "libavutil/avassert.h"
30 #include "libavutil/internal.h"
31 
32 typedef struct VCR1Context {
33  int delta[16];
34  int offset[4];
35 } VCR1Context;
36 
38 {
39  avctx->pix_fmt = AV_PIX_FMT_YUV410P;
40 
41  if (avctx->width % 8 || avctx->height%4) {
42  avpriv_request_sample(avctx, "odd dimensions (%d x %d) support", avctx->width, avctx->height);
43  return AVERROR_INVALIDDATA;
44  }
45 
46  return 0;
47 }
48 
49 static int vcr1_decode_frame(AVCodecContext *avctx, void *data,
50  int *got_frame, AVPacket *avpkt)
51 {
52  VCR1Context *const a = avctx->priv_data;
53  AVFrame *const p = data;
54  const uint8_t *bytestream = avpkt->data;
55  const uint8_t *bytestream_end = bytestream + avpkt->size;
56  int i, x, y, ret;
57 
58  if(avpkt->size < 32 + avctx->height + avctx->width*avctx->height*5/8){
59  av_log(avctx, AV_LOG_ERROR, "Insufficient input data. %d < %d\n", avpkt->size , 32 + avctx->height + avctx->width*avctx->height*5/8);
60  return AVERROR(EINVAL);
61  }
62 
63  if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
64  return ret;
66  p->key_frame = 1;
67 
68  for (i = 0; i < 16; i++) {
69  a->delta[i] = *bytestream++;
70  bytestream++;
71  }
72 
73  for (y = 0; y < avctx->height; y++) {
74  int offset;
75  uint8_t *luma = &p->data[0][y * p->linesize[0]];
76 
77  if ((y & 3) == 0) {
78  uint8_t *cb = &p->data[1][(y >> 2) * p->linesize[1]];
79  uint8_t *cr = &p->data[2][(y >> 2) * p->linesize[2]];
80 
81  av_assert0 (bytestream_end - bytestream >= 4 + avctx->width);
82 
83  for (i = 0; i < 4; i++)
84  a->offset[i] = *bytestream++;
85 
86  offset = a->offset[0] - a->delta[bytestream[2] & 0xF];
87  for (x = 0; x < avctx->width; x += 4) {
88  luma[0] = offset += a->delta[bytestream[2] & 0xF];
89  luma[1] = offset += a->delta[bytestream[2] >> 4];
90  luma[2] = offset += a->delta[bytestream[0] & 0xF];
91  luma[3] = offset += a->delta[bytestream[0] >> 4];
92  luma += 4;
93 
94  *cb++ = bytestream[3];
95  *cr++ = bytestream[1];
96 
97  bytestream += 4;
98  }
99  } else {
100  av_assert0 (bytestream_end - bytestream >= avctx->width / 2);
101 
102  offset = a->offset[y & 3] - a->delta[bytestream[2] & 0xF];
103 
104  for (x = 0; x < avctx->width; x += 8) {
105  luma[0] = offset += a->delta[bytestream[2] & 0xF];
106  luma[1] = offset += a->delta[bytestream[2] >> 4];
107  luma[2] = offset += a->delta[bytestream[3] & 0xF];
108  luma[3] = offset += a->delta[bytestream[3] >> 4];
109  luma[4] = offset += a->delta[bytestream[0] & 0xF];
110  luma[5] = offset += a->delta[bytestream[0] >> 4];
111  luma[6] = offset += a->delta[bytestream[1] & 0xF];
112  luma[7] = offset += a->delta[bytestream[1] >> 4];
113  luma += 8;
114  bytestream += 4;
115  }
116  }
117  }
118 
119  *got_frame = 1;
120 
121  return bytestream - avpkt->data;
122 }
123 
125  .name = "vcr1",
126  .long_name = NULL_IF_CONFIG_SMALL("ATI VCR1"),
127  .type = AVMEDIA_TYPE_VIDEO,
128  .id = AV_CODEC_ID_VCR1,
129  .priv_data_size = sizeof(VCR1Context),
132  .capabilities = AV_CODEC_CAP_DR1,
133 };
#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:295
ptrdiff_t const GLvoid * data
Definition: opengl_enc.c:100
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
#define avpriv_request_sample(...)
int size
Definition: avcodec.h:1481
static av_cold int vcr1_decode_init(AVCodecContext *avctx)
Definition: vcr1.c:37
The reader does not expect b to be semantically here and if the code is changed by maybe adding a a division or other the signedness will almost certainly be mistaken To avoid this confusion a new type was SUINT is the C unsigned type but it holds a signed int to use the same example SUINT a
Definition: undefined.txt:36
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:1778
AVCodec.
Definition: avcodec.h:3484
static void decode(AVCodecContext *dec_ctx, AVPacket *pkt, AVFrame *frame, FILE *outfile)
Definition: decode_audio.c:71
int offset[4]
Definition: vcr1.c:34
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:37
static double cb(void *priv, double x, double y)
Definition: vf_geq.c:112
uint8_t
#define av_cold
Definition: attributes.h:82
uint8_t * data
Definition: avcodec.h:1480
#define av_log(a,...)
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
simple assert() macros that are a bit more flexible than ISO C assert().
const char * name
Name of the codec implementation.
Definition: avcodec.h:3491
common internal API header
enum AVPictureType pict_type
Picture type of the frame.
Definition: frame.h:378
int width
picture width / height.
Definition: avcodec.h:1741
int delta[16]
Definition: vcr1.c:33
Libavcodec external API header.
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:326
main external API structure.
Definition: avcodec.h:1568
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: decode.c:1963
planar YUV 4:1:0, 9bpp, (1 Cr & Cb sample per 4x4 Y samples)
Definition: pixfmt.h:72
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:309
AVCodec ff_vcr1_decoder
Definition: vcr1.c:124
common internal api header.
static int vcr1_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: vcr1.c:49
void * priv_data
Definition: avcodec.h:1595
int key_frame
1 -> keyframe, 0-> not
Definition: frame.h:373
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later.That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another.Frame references ownership and permissions
static double cr(void *priv, double x, double y)
Definition: vf_geq.c:113
This structure stores compressed data.
Definition: avcodec.h:1457
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:984
for(j=16;j >0;--j)