FFmpeg
cyuv.c
Go to the documentation of this file.
1 /*
2  * Creative YUV (CYUV) Video Decoder
3  * by Mike Melanson (melanson@pcisys.net)
4  * based on "Creative YUV (CYUV) stream format for AVI":
5  * http://www.csse.monash.edu.au/~timf/videocodec/cyuv.txt
6  *
7  * Copyright (C) 2003 The FFmpeg project
8  *
9  * This file is part of FFmpeg.
10  *
11  * FFmpeg is free software; you can redistribute it and/or
12  * modify it under the terms of the GNU Lesser General Public
13  * License as published by the Free Software Foundation; either
14  * version 2.1 of the License, or (at your option) any later version.
15  *
16  * FFmpeg is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19  * Lesser General Public License for more details.
20  *
21  * You should have received a copy of the GNU Lesser General Public
22  * License along with FFmpeg; if not, write to the Free Software
23  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24  */
25 
26 /**
27  * @file
28  * Creative YUV (CYUV) Video Decoder.
29  */
30 
31 #include <stdio.h>
32 #include <stdlib.h>
33 #include <string.h>
34 
35 #include "avcodec.h"
36 #include "internal.h"
37 #include "libavutil/internal.h"
38 
39 
40 typedef struct CyuvDecodeContext {
41  AVCodecContext *avctx;
42  int width, height;
43 } CyuvDecodeContext;
44 
45 static av_cold int cyuv_decode_init(AVCodecContext *avctx)
46 {
47  CyuvDecodeContext *s = avctx->priv_data;
48 
49  s->avctx = avctx;
50  s->width = avctx->width;
51  /* width needs to be divisible by 4 for this codec to work */
52  if (s->width & 0x3)
53  return AVERROR_INVALIDDATA;
54  s->height = avctx->height;
55 
56  return 0;
57 }
58 
59 static int cyuv_decode_frame(AVCodecContext *avctx,
60  void *data, int *got_frame,
61  AVPacket *avpkt)
62 {
63  const uint8_t *buf = avpkt->data;
64  int buf_size = avpkt->size;
65  CyuvDecodeContext *s=avctx->priv_data;
66  AVFrame *frame = data;
67 
68  unsigned char *y_plane;
69  unsigned char *u_plane;
70  unsigned char *v_plane;
71  int y_ptr;
72  int u_ptr;
73  int v_ptr;
74 
75  /* prediction error tables (make it clear that they are signed values) */
76  const signed char *y_table = (const signed char*)buf + 0;
77  const signed char *u_table = (const signed char*)buf + 16;
78  const signed char *v_table = (const signed char*)buf + 32;
79 
80  unsigned char y_pred, u_pred, v_pred;
81  int stream_ptr;
82  unsigned char cur_byte;
83  int pixel_groups;
84  int rawsize = s->height * FFALIGN(s->width,2) * 2;
85  int ret;
86 
87  if (avctx->codec_id == AV_CODEC_ID_AURA) {
88  y_table = u_table;
89  u_table = v_table;
90  }
91  /* sanity check the buffer size: A buffer has 3x16-bytes tables
92  * followed by (height) lines each with 3 bytes to represent groups
93  * of 4 pixels. Thus, the total size of the buffer ought to be:
94  * (3 * 16) + height * (width * 3 / 4) */
95  if (buf_size == 48 + s->height * (s->width * 3 / 4)) {
96  avctx->pix_fmt = AV_PIX_FMT_YUV411P;
97  } else if(buf_size == rawsize ) {
98  avctx->pix_fmt = AV_PIX_FMT_UYVY422;
99  } else {
100  av_log(avctx, AV_LOG_ERROR, "got a buffer with %d bytes when %d were expected\n",
101  buf_size, 48 + s->height * (s->width * 3 / 4));
102  return AVERROR_INVALIDDATA;
103  }
104 
105  /* pixel data starts 48 bytes in, after 3x16-byte tables */
106  stream_ptr = 48;
107 
108  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
109  return ret;
110 
111  y_plane = frame->data[0];
112  u_plane = frame->data[1];
113  v_plane = frame->data[2];
114 
115  if (buf_size == rawsize) {
116  int linesize = FFALIGN(s->width,2) * 2;
117  y_plane += frame->linesize[0] * s->height;
118  for (stream_ptr = 0; stream_ptr < rawsize; stream_ptr += linesize) {
119  y_plane -= frame->linesize[0];
120  memcpy(y_plane, buf+stream_ptr, linesize);
121  }
122  } else {
123 
124  /* iterate through each line in the height */
125  for (y_ptr = 0, u_ptr = 0, v_ptr = 0;
126  y_ptr < (s->height * frame->linesize[0]);
127  y_ptr += frame->linesize[0] - s->width,
128  u_ptr += frame->linesize[1] - s->width / 4,
129  v_ptr += frame->linesize[2] - s->width / 4) {
130 
131  /* reset predictors */
132  cur_byte = buf[stream_ptr++];
133  u_plane[u_ptr++] = u_pred = cur_byte & 0xF0;
134  y_plane[y_ptr++] = y_pred = (cur_byte & 0x0F) << 4;
135 
136  cur_byte = buf[stream_ptr++];
137  v_plane[v_ptr++] = v_pred = cur_byte & 0xF0;
138  y_pred += y_table[cur_byte & 0x0F];
139  y_plane[y_ptr++] = y_pred;
140 
141  cur_byte = buf[stream_ptr++];
142  y_pred += y_table[cur_byte & 0x0F];
143  y_plane[y_ptr++] = y_pred;
144  y_pred += y_table[(cur_byte & 0xF0) >> 4];
145  y_plane[y_ptr++] = y_pred;
146 
147  /* iterate through the remaining pixel groups (4 pixels/group) */
148  pixel_groups = s->width / 4 - 1;
149  while (pixel_groups--) {
150 
151  cur_byte = buf[stream_ptr++];
152  u_pred += u_table[(cur_byte & 0xF0) >> 4];
153  u_plane[u_ptr++] = u_pred;
154  y_pred += y_table[cur_byte & 0x0F];
155  y_plane[y_ptr++] = y_pred;
156 
157  cur_byte = buf[stream_ptr++];
158  v_pred += v_table[(cur_byte & 0xF0) >> 4];
159  v_plane[v_ptr++] = v_pred;
160  y_pred += y_table[cur_byte & 0x0F];
161  y_plane[y_ptr++] = y_pred;
162 
163  cur_byte = buf[stream_ptr++];
164  y_pred += y_table[cur_byte & 0x0F];
165  y_plane[y_ptr++] = y_pred;
166  y_pred += y_table[(cur_byte & 0xF0) >> 4];
167  y_plane[y_ptr++] = y_pred;
168 
169  }
170  }
171  }
172 
173  *got_frame = 1;
174 
175  return buf_size;
176 }
177 
178 #if CONFIG_AURA_DECODER
179 const AVCodec ff_aura_decoder = {
180  .name = "aura",
181  .long_name = NULL_IF_CONFIG_SMALL("Auravision AURA"),
182  .type = AVMEDIA_TYPE_VIDEO,
183  .id = AV_CODEC_ID_AURA,
184  .priv_data_size = sizeof(CyuvDecodeContext),
185  .init = cyuv_decode_init,
186  .decode = cyuv_decode_frame,
187  .capabilities = AV_CODEC_CAP_DR1,
188  .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
189 };
190 #endif
191 
192 #if CONFIG_CYUV_DECODER
193 const AVCodec ff_cyuv_decoder = {
194  .name = "cyuv",
195  .long_name = NULL_IF_CONFIG_SMALL("Creative YUV (CYUV)"),
196  .type = AVMEDIA_TYPE_VIDEO,
197  .id = AV_CODEC_ID_CYUV,
198  .priv_data_size = sizeof(CyuvDecodeContext),
199  .init = cyuv_decode_init,
200  .decode = cyuv_decode_frame,
201  .capabilities = AV_CODEC_CAP_DR1,
202  .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
203 };
204 #endif
AVCodec
AVCodec.
Definition: codec.h:202
ff_aura_decoder
const AVCodec ff_aura_decoder
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:42
init
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:31
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:303
internal.h
AVPacket::data
uint8_t * data
Definition: packet.h:373
data
const char data[16]
Definition: mxf.c:143
CyuvDecodeContext
Definition: cyuv.c:40
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
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
s
#define s(width, name)
Definition: cbs_vp9.c:257
CyuvDecodeContext::width
int width
Definition: cyuv.c:42
cyuv_decode_init
static av_cold int cyuv_decode_init(AVCodecContext *avctx)
Definition: cyuv.c:45
AVCodecContext::codec_id
enum AVCodecID codec_id
Definition: avcodec.h:393
cyuv_decode_frame
static int cyuv_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
Definition: cyuv.c:59
CyuvDecodeContext::avctx
AVCodecContext * avctx
Definition: cyuv.c:41
ff_get_buffer
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: decode.c:1652
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:374
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
AV_CODEC_ID_CYUV
@ AV_CODEC_ID_CYUV
Definition: codec_id.h:76
ff_cyuv_decoder
const AVCodec ff_cyuv_decoder
internal.h
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:209
AVCodecContext::height
int height
Definition: avcodec.h:556
AVCodecContext::pix_fmt
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:593
avcodec.h
ret
ret
Definition: filter_design.txt:187
frame
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several the filter must be ready for frames arriving randomly on any input any filter with several inputs will most likely require some kind of queuing mechanism It is perfectly acceptable to have a limited queue and to drop frames when the inputs are too unbalanced request_frame For filters that do not use the this method is called when a frame is wanted on an output For a it should directly call filter_frame on the corresponding output For a if there are queued frames already one of these frames should be pushed If the filter should request a frame on one of its repeatedly until at least one frame has been pushed Return or at least make progress towards producing a frame
Definition: filter_design.txt:264
AV_PIX_FMT_UYVY422
@ AV_PIX_FMT_UYVY422
packed YUV 4:2:2, 16bpp, Cb Y0 Cr Y1
Definition: pixfmt.h:81
AVCodecContext
main external API structure.
Definition: avcodec.h:383
CyuvDecodeContext::height
int height
Definition: cyuv.c:42
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
FFALIGN
#define FFALIGN(x, a)
Definition: macros.h:78
AVPacket
This structure stores compressed data.
Definition: packet.h:350
AVCodecContext::priv_data
void * priv_data
Definition: avcodec.h:410
AV_PIX_FMT_YUV411P
@ AV_PIX_FMT_YUV411P
planar YUV 4:1:1, 12bpp, (1 Cr & Cb sample per 4x1 Y samples)
Definition: pixfmt.h:73
AVCodecContext::width
int width
picture width / height.
Definition: avcodec.h:556
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:61
AV_CODEC_ID_AURA
@ AV_CODEC_ID_AURA
Definition: codec_id.h:173
Generated on Tue Oct 19 2021 19:21:19 for FFmpeg by   doxygen 1.8.17