FFmpeg
aura.c
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1 /*
2  * Aura 2 decoder
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 /**
22  * @file
23  * Aura 2 decoder
24  */
25 
26 #include "avcodec.h"
27 #include "internal.h"
28 #include "libavutil/internal.h"
29 
31 {
32  /* width needs to be divisible by 4 for this codec to work */
33  if (avctx->width & 0x3)
34  return AVERROR(EINVAL);
35  avctx->pix_fmt = AV_PIX_FMT_YUV422P;
36 
37  return 0;
38 }
39 
41  void *data, int *got_frame,
42  AVPacket *pkt)
43 {
44  AVFrame *frame = data;
45  uint8_t *Y, *U, *V;
46  uint8_t val;
47  int x, y, ret;
48  const uint8_t *buf = pkt->data;
49 
50  /* prediction error tables (make it clear that they are signed values) */
51  const int8_t *delta_table = (const int8_t*)buf + 16;
52 
53  if (pkt->size != 48 + avctx->height * avctx->width) {
54  av_log(avctx, AV_LOG_ERROR, "got a buffer with %d bytes when %d were expected\n",
55  pkt->size, 48 + avctx->height * avctx->width);
56  return AVERROR_INVALIDDATA;
57  }
58 
59  /* pixel data starts 48 bytes in, after 3x16-byte tables */
60  buf += 48;
61 
62  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
63  return ret;
64 
65  Y = frame->data[0];
66  U = frame->data[1];
67  V = frame->data[2];
68 
69  /* iterate through each line in the height */
70  for (y = 0; y < avctx->height; y++) {
71  /* reset predictors */
72  val = *buf++;
73  U[0] = val & 0xF0;
74  Y[0] = val << 4;
75  val = *buf++;
76  V[0] = val & 0xF0;
77  Y[1] = Y[0] + delta_table[val & 0xF];
78  Y += 2; U++; V++;
79 
80  /* iterate through the remaining pixel groups (4 pixels/group) */
81  for (x = 1; x < (avctx->width >> 1); x++) {
82  val = *buf++;
83  U[0] = U[-1] + delta_table[val >> 4];
84  Y[0] = Y[-1] + delta_table[val & 0xF];
85  val = *buf++;
86  V[0] = V[-1] + delta_table[val >> 4];
87  Y[1] = Y[ 0] + delta_table[val & 0xF];
88  Y += 2; U++; V++;
89  }
90  Y += frame->linesize[0] - avctx->width;
91  U += frame->linesize[1] - (avctx->width >> 1);
92  V += frame->linesize[2] - (avctx->width >> 1);
93  }
94 
95  *got_frame = 1;
96 
97  return pkt->size;
98 }
99 
101  .name = "aura2",
102  .long_name = NULL_IF_CONFIG_SMALL("Auravision Aura 2"),
103  .type = AVMEDIA_TYPE_VIDEO,
104  .id = AV_CODEC_ID_AURA2,
105  .init = aura_decode_init,
106  .decode = aura_decode_frame,
107  .capabilities = AV_CODEC_CAP_DR1,
108  .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
109 };
const char const char void * val
Definition: avisynth_c.h:863
#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 aura_decode_init(AVCodecContext *avctx)
Definition: aura.c:30
int size
Definition: avcodec.h:1478
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:1775
static AVPacket pkt
AVCodec ff_aura2_decoder
Definition: aura.c:100
AVCodec.
Definition: avcodec.h:3481
#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:40
uint8_t
#define av_cold
Definition: attributes.h:82
uint8_t * data
Definition: avcodec.h:1477
#define av_log(a,...)
#define U(x)
Definition: vp56_arith.h:37
#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
const char * name
Name of the codec implementation.
Definition: avcodec.h:3488
planar YUV 4:2:2, 16bpp, (1 Cr & Cb sample per 2x1 Y samples)
Definition: pixfmt.h:70
common internal API header
#define Y
Definition: boxblur.h:38
int width
picture width / height.
Definition: avcodec.h:1738
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
Libavcodec external API header.
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:326
static int aura_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *pkt)
Definition: aura.c:40
main external API structure.
Definition: avcodec.h:1565
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: decode.c:1963
void * buf
Definition: avisynth_c.h:766
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:309
common internal api header.
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
This structure stores compressed data.
Definition: avcodec.h:1454
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:981
#define V
Definition: avdct.c:30