FFmpeg
vcr1.c
Go to the documentation of this file.
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  .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
134 };
AVCodec
AVCodec.
Definition: codec.h:197
FF_CODEC_CAP_INIT_THREADSAFE
#define FF_CODEC_CAP_INIT_THREADSAFE
The codec does not modify any global variables in the init function, allowing to call the init functi...
Definition: internal.h:41
init
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:31
AVERROR
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
cb
static double cb(void *priv, double x, double y)
Definition: vf_geq.c:215
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:303
ff_vcr1_decoder
const AVCodec ff_vcr1_decoder
Definition: vcr1.c:124
internal.h
AVPacket::data
uint8_t * data
Definition: packet.h:365
data
const char data[16]
Definition: mxf.c:142
AVFrame::data
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:317
AVFrame::key_frame
int key_frame
1 -> keyframe, 0-> not
Definition: frame.h:381
VCR1Context
Definition: vcr1.c:32
avassert.h
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:181
av_cold
#define av_cold
Definition: attributes.h:90
decode
static void decode(AVCodecContext *dec_ctx, AVPacket *pkt, AVFrame *frame, FILE *outfile)
Definition: decode_audio.c:71
av_assert0
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:37
AV_PICTURE_TYPE_I
@ AV_PICTURE_TYPE_I
Intra.
Definition: avutil.h:274
AV_CODEC_ID_VCR1
@ AV_CODEC_ID_VCR1
Definition: codec_id.h:84
for
for(j=16;j >0;--j)
Definition: h264pred_template.c:469
AVFrame::pict_type
enum AVPictureType pict_type
Picture type of the frame.
Definition: frame.h:386
ff_get_buffer
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: decode.c:1638
AV_CODEC_CAP_DR1
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() or get_encode_buffer() for allocating buffers and supports custom allocators.
Definition: codec.h:52
AVPacket::size
int size
Definition: packet.h:366
vcr1_decode_frame
static int vcr1_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: vcr1.c:49
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
VCR1Context::offset
int offset[4]
Definition: vcr1.c:34
a
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:41
offset
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf offset
Definition: writing_filters.txt:86
VCR1Context::delta
int delta[16]
Definition: vcr1.c:33
i
int i
Definition: input.c:407
internal.h
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:204
AVCodecContext::height
int height
Definition: avcodec.h:674
vcr1_decode_init
static av_cold int vcr1_decode_init(AVCodecContext *avctx)
Definition: vcr1.c:37
AVCodecContext::pix_fmt
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:711
avcodec.h
ret
ret
Definition: filter_design.txt:187
AVCodecContext
main external API structure.
Definition: avcodec.h:501
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
avpriv_request_sample
#define avpriv_request_sample(...)
Definition: tableprint_vlc.h:39
AVCodecContext::priv_data
void * priv_data
Definition: avcodec.h:528
AVPacket
This structure stores compressed data.
Definition: packet.h:342
cr
static double cr(void *priv, double x, double y)
Definition: vf_geq.c:216
AVCodecContext::width
int width
picture width / height.
Definition: avcodec.h:674
AVFrame::linesize
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:334
AV_PIX_FMT_YUV410P
@ AV_PIX_FMT_YUV410P
planar YUV 4:1:0, 9bpp, (1 Cr & Cb sample per 4x4 Y samples)
Definition: pixfmt.h:72
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59