FFmpeg  4.0
v4l2_m2m_dec.c
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1 /*
2  * V4L2 mem2mem decoders
3  *
4  * Copyright (C) 2017 Alexis Ballier <aballier@gentoo.org>
5  * Copyright (C) 2017 Jorge Ramirez <jorge.ramirez-ortiz@linaro.org>
6  *
7  * This file is part of FFmpeg.
8  *
9  * FFmpeg is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU Lesser General Public
11  * License as published by the Free Software Foundation; either
12  * version 2.1 of the License, or (at your option) any later version.
13  *
14  * FFmpeg is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17  * Lesser General Public License for more details.
18  *
19  * You should have received a copy of the GNU Lesser General Public
20  * License along with FFmpeg; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22  */
23 
24 #include <linux/videodev2.h>
25 #include <sys/ioctl.h>
26 #include "libavutil/pixfmt.h"
27 #include "libavutil/pixdesc.h"
28 #include "libavutil/opt.h"
29 #include "libavcodec/avcodec.h"
30 #include "libavcodec/decode.h"
31 
32 #include "v4l2_context.h"
33 #include "v4l2_m2m.h"
34 #include "v4l2_fmt.h"
35 
36 static int v4l2_try_start(AVCodecContext *avctx)
37 {
38  V4L2m2mContext *s = ((V4L2m2mPriv*)avctx->priv_data)->context;
39  V4L2Context *const capture = &s->capture;
40  V4L2Context *const output = &s->output;
41  struct v4l2_selection selection;
42  int ret;
43 
44  /* 1. start the output process */
45  if (!output->streamon) {
46  ret = ff_v4l2_context_set_status(output, VIDIOC_STREAMON);
47  if (ret < 0) {
48  av_log(avctx, AV_LOG_DEBUG, "VIDIOC_STREAMON on output context\n");
49  return ret;
50  }
51  }
52 
53  if (capture->streamon)
54  return 0;
55 
56  /* 2. get the capture format */
57  capture->format.type = capture->type;
58  ret = ioctl(s->fd, VIDIOC_G_FMT, &capture->format);
59  if (ret) {
60  av_log(avctx, AV_LOG_WARNING, "VIDIOC_G_FMT ioctl\n");
61  return ret;
62  }
63 
64  /* 2.1 update the AVCodecContext */
65  avctx->pix_fmt = ff_v4l2_format_v4l2_to_avfmt(capture->format.fmt.pix_mp.pixelformat, AV_CODEC_ID_RAWVIDEO);
66  capture->av_pix_fmt = avctx->pix_fmt;
67 
68  /* 3. set the crop parameters */
69  selection.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
70  selection.r.height = avctx->coded_height;
71  selection.r.width = avctx->coded_width;
72  ret = ioctl(s->fd, VIDIOC_S_SELECTION, &selection);
73  if (!ret) {
74  ret = ioctl(s->fd, VIDIOC_G_SELECTION, &selection);
75  if (ret) {
76  av_log(avctx, AV_LOG_WARNING, "VIDIOC_G_SELECTION ioctl\n");
77  } else {
78  av_log(avctx, AV_LOG_DEBUG, "crop output %dx%d\n", selection.r.width, selection.r.height);
79  /* update the size of the resulting frame */
80  capture->height = selection.r.height;
81  capture->width = selection.r.width;
82  }
83  }
84 
85  /* 4. init the capture context now that we have the capture format */
86  if (!capture->buffers) {
87  ret = ff_v4l2_context_init(capture);
88  if (ret) {
89  av_log(avctx, AV_LOG_DEBUG, "can't request output buffers\n");
90  return ret;
91  }
92  }
93 
94  /* 5. start the capture process */
95  ret = ff_v4l2_context_set_status(capture, VIDIOC_STREAMON);
96  if (ret) {
97  av_log(avctx, AV_LOG_DEBUG, "VIDIOC_STREAMON, on capture context\n");
98  return ret;
99  }
100 
101  return 0;
102 }
103 
105 {
106  struct v4l2_event_subscription sub;
107  V4L2Context *output = &s->output;
108  int ret;
109 
110  /**
111  * requirements
112  */
113  memset(&sub, 0, sizeof(sub));
114  sub.type = V4L2_EVENT_SOURCE_CHANGE;
115  ret = ioctl(s->fd, VIDIOC_SUBSCRIBE_EVENT, &sub);
116  if ( ret < 0) {
117  if (output->height == 0 || output->width == 0) {
119  "the v4l2 driver does not support VIDIOC_SUBSCRIBE_EVENT\n"
120  "you must provide codec_height and codec_width on input\n");
121  return ret;
122  }
123  }
124 
125  return 0;
126 }
127 
129 {
130  V4L2m2mContext *s = ((V4L2m2mPriv*)avctx->priv_data)->context;
131  V4L2Context *const capture = &s->capture;
132  V4L2Context *const output = &s->output;
133  AVPacket avpkt = {0};
134  int ret;
135 
136  ret = ff_decode_get_packet(avctx, &avpkt);
137  if (ret < 0 && ret != AVERROR_EOF)
138  return ret;
139 
140  if (s->draining)
141  goto dequeue;
142 
143  ret = ff_v4l2_context_enqueue_packet(output, &avpkt);
144  if (ret < 0) {
145  if (ret != AVERROR(ENOMEM))
146  return ret;
147  /* no input buffers available, continue dequeing */
148  }
149 
150  if (avpkt.size) {
151  ret = v4l2_try_start(avctx);
152  if (ret)
153  return 0;
154  }
155 
156 dequeue:
157  return ff_v4l2_context_dequeue_frame(capture, frame);
158 }
159 
161 {
162  V4L2Context *capture, *output;
163  V4L2m2mContext *s;
164  int ret;
165 
166  ret = ff_v4l2_m2m_create_context(avctx, &s);
167  if (ret < 0)
168  return ret;
169 
170  capture = &s->capture;
171  output = &s->output;
172 
173  /* if these dimensions are invalid (ie, 0 or too small) an event will be raised
174  * by the v4l2 driver; this event will trigger a full pipeline reconfig and
175  * the proper values will be retrieved from the kernel driver.
176  */
177  output->height = capture->height = avctx->coded_height;
178  output->width = capture->width = avctx->coded_width;
179 
180  output->av_codec_id = avctx->codec_id;
181  output->av_pix_fmt = AV_PIX_FMT_NONE;
182 
184  capture->av_pix_fmt = avctx->pix_fmt;
185 
186  ret = ff_v4l2_m2m_codec_init(avctx);
187  if (ret) {
188  av_log(avctx, AV_LOG_ERROR, "can't configure decoder\n");
189  return ret;
190  }
191 
192  return v4l2_prepare_decoder(s);
193 }
194 
195 #define OFFSET(x) offsetof(V4L2m2mPriv, x)
196 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_DECODING_PARAM
197 
198 static const AVOption options[] = {
200  { "num_capture_buffers", "Number of buffers in the capture context",
201  OFFSET(num_capture_buffers), AV_OPT_TYPE_INT, {.i64 = 20}, 20, INT_MAX, FLAGS },
202  { NULL},
203 };
204 
205 #define M2MDEC(NAME, LONGNAME, CODEC, bsf_name) \
206 static const AVClass v4l2_m2m_ ## NAME ## _dec_class = {\
207  .class_name = #NAME "_v4l2_m2m_decoder",\
208  .item_name = av_default_item_name,\
209  .option = options,\
210  .version = LIBAVUTIL_VERSION_INT,\
211 };\
212 \
213 AVCodec ff_ ## NAME ## _v4l2m2m_decoder = { \
214  .name = #NAME "_v4l2m2m" ,\
215  .long_name = NULL_IF_CONFIG_SMALL("V4L2 mem2mem " LONGNAME " decoder wrapper"),\
216  .type = AVMEDIA_TYPE_VIDEO,\
217  .id = CODEC ,\
218  .priv_data_size = sizeof(V4L2m2mPriv),\
219  .priv_class = &v4l2_m2m_ ## NAME ## _dec_class,\
220  .init = v4l2_decode_init,\
221  .receive_frame = v4l2_receive_frame,\
222  .close = ff_v4l2_m2m_codec_end,\
223  .bsfs = bsf_name, \
224  .capabilities = AV_CODEC_CAP_HARDWARE | AV_CODEC_CAP_DELAY, \
225  .wrapper_name = "v4l2m2m", \
226 };
227 
228 M2MDEC(h264, "H.264", AV_CODEC_ID_H264, "h264_mp4toannexb");
229 M2MDEC(hevc, "HEVC", AV_CODEC_ID_HEVC, "hevc_mp4toannexb");
230 M2MDEC(mpeg1, "MPEG1", AV_CODEC_ID_MPEG1VIDEO, NULL);
231 M2MDEC(mpeg2, "MPEG2", AV_CODEC_ID_MPEG2VIDEO, NULL);
232 M2MDEC(mpeg4, "MPEG4", AV_CODEC_ID_MPEG4, NULL);
233 M2MDEC(h263, "H.263", AV_CODEC_ID_H263, NULL);
234 M2MDEC(vc1 , "VC1", AV_CODEC_ID_VC1, NULL);
235 M2MDEC(vp8, "VP8", AV_CODEC_ID_VP8, NULL);
236 M2MDEC(vp9, "VP9", AV_CODEC_ID_VP9, NULL);
enum AVPixelFormat ff_v4l2_format_v4l2_to_avfmt(uint32_t v4l2_fmt, enum AVCodecID avcodec)
Definition: v4l2_fmt.c:132
#define NULL
Definition: coverity.c:32
const char * s
Definition: avisynth_c.h:768
static const AVOption options[]
Definition: v4l2_m2m_dec.c:198
This structure describes decoded (raw) audio or video data.
Definition: frame.h:218
AVOption.
Definition: opt.h:246
AVCodecContext * avctx
Definition: v4l2_m2m.h:52
int coded_width
Bitstream width / height, may be different from width/height e.g.
Definition: avcodec.h:1705
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:182
int ff_v4l2_context_init(V4L2Context *ctx)
Initializes a V4L2Context.
Definition: v4l2_context.c:661
int size
Definition: avcodec.h:1431
#define FLAGS
Definition: v4l2_m2m_dec.c:196
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:1727
int ff_v4l2_context_dequeue_frame(V4L2Context *ctx, AVFrame *frame)
Dequeues a buffer from a V4L2Context to an AVFrame.
Definition: v4l2_context.c:574
int width
Width and height of the frames it produces (in case of a capture context, e.g.
Definition: v4l2_context.h:71
int ff_v4l2_m2m_codec_init(AVCodecContext *avctx)
Probes the video nodes looking for the required codec capabilities.
Definition: v4l2_m2m.c:341
enum AVCodecID av_codec_id
AVCodecID corresponding to this buffer context.
Definition: v4l2_context.h:59
#define av_cold
Definition: attributes.h:82
AVOptions.
#define OFFSET(x)
Definition: v4l2_m2m_dec.c:195
static int v4l2_receive_frame(AVCodecContext *avctx, AVFrame *frame)
Definition: v4l2_m2m_dec.c:128
int ff_decode_get_packet(AVCodecContext *avctx, AVPacket *pkt)
Called by decoders to get the next packet for decoding.
Definition: decode.c:294
static AVFrame * frame
#define AVERROR_EOF
End of file.
Definition: error.h:55
#define av_log(a,...)
int ff_v4l2_m2m_create_context(AVCodecContext *avctx, V4L2m2mContext **s)
Allocate a new context and references for a V4L2 M2M instance.
Definition: v4l2_m2m.c:382
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
#define AVERROR(e)
Definition: error.h:43
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:197
enum AVPixelFormat av_pix_fmt
AVPixelFormat corresponding to this buffer context.
Definition: v4l2_context.h:53
V4L2Buffer * buffers
Indexed array of V4L2Buffers.
Definition: v4l2_context.h:76
int streamon
Whether the stream has been started (VIDIOC_STREAMON has been sent).
Definition: v4l2_context.h:86
int ff_v4l2_context_enqueue_packet(V4L2Context *ctx, const AVPacket *pkt)
Enqueues a buffer to a V4L2Context from an AVPacket.
Definition: v4l2_context.c:549
preferred ID for MPEG-1/2 video decoding
Definition: avcodec.h:220
struct v4l2_format format
Format returned by the driver after initializing the buffer context.
Definition: v4l2_context.h:65
int ff_v4l2_context_set_status(V4L2Context *ctx, uint32_t cmd)
Sets the status of a V4L2Context.
Definition: v4l2_context.c:510
static int v4l2_try_start(AVCodecContext *avctx)
Definition: v4l2_m2m_dec.c:36
V4L2Context capture
Definition: v4l2_m2m.h:48
Libavcodec external API header.
enum AVCodecID codec_id
Definition: avcodec.h:1528
main external API structure.
Definition: avcodec.h:1518
int coded_height
Definition: avcodec.h:1705
#define M2MDEC(NAME, LONGNAME, CODEC, bsf_name)
Definition: v4l2_m2m_dec.c:205
static int v4l2_prepare_decoder(V4L2m2mContext *s)
Definition: v4l2_m2m_dec.c:104
static av_cold int v4l2_decode_init(AVCodecContext *avctx)
Definition: v4l2_m2m_dec.c:160
V4L2Context output
Definition: v4l2_m2m.h:49
void * priv_data
Definition: avcodec.h:1545
pixel format definitions
#define V4L_M2M_DEFAULT_OPTS
Definition: v4l2_m2m.h:39
This structure stores compressed data.
Definition: avcodec.h:1407
enum v4l2_buf_type type
Type of this buffer context.
Definition: v4l2_context.h:47