FFmpeg  4.3
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 #include "libavcodec/internal.h"
32 
33 #include "v4l2_context.h"
34 #include "v4l2_m2m.h"
35 #include "v4l2_fmt.h"
36 
37 static int v4l2_try_start(AVCodecContext *avctx)
38 {
39  V4L2m2mContext *s = ((V4L2m2mPriv*)avctx->priv_data)->context;
40  V4L2Context *const capture = &s->capture;
41  V4L2Context *const output = &s->output;
42  struct v4l2_selection selection = { 0 };
43  int ret;
44 
45  /* 1. start the output process */
46  if (!output->streamon) {
47  ret = ff_v4l2_context_set_status(output, VIDIOC_STREAMON);
48  if (ret < 0) {
49  av_log(avctx, AV_LOG_DEBUG, "VIDIOC_STREAMON on output context\n");
50  return ret;
51  }
52  }
53 
54  if (capture->streamon)
55  return 0;
56 
57  /* 2. get the capture format */
58  capture->format.type = capture->type;
59  ret = ioctl(s->fd, VIDIOC_G_FMT, &capture->format);
60  if (ret) {
61  av_log(avctx, AV_LOG_WARNING, "VIDIOC_G_FMT ioctl\n");
62  return ret;
63  }
64 
65  /* 2.1 update the AVCodecContext */
66  avctx->pix_fmt = ff_v4l2_format_v4l2_to_avfmt(capture->format.fmt.pix_mp.pixelformat, AV_CODEC_ID_RAWVIDEO);
67  capture->av_pix_fmt = avctx->pix_fmt;
68 
69  /* 3. set the crop parameters */
70  selection.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
71  selection.r.height = avctx->coded_height;
72  selection.r.width = avctx->coded_width;
73  ret = ioctl(s->fd, VIDIOC_S_SELECTION, &selection);
74  if (!ret) {
75  ret = ioctl(s->fd, VIDIOC_G_SELECTION, &selection);
76  if (ret) {
77  av_log(avctx, AV_LOG_WARNING, "VIDIOC_G_SELECTION ioctl\n");
78  } else {
79  av_log(avctx, AV_LOG_DEBUG, "crop output %dx%d\n", selection.r.width, selection.r.height);
80  /* update the size of the resulting frame */
81  capture->height = selection.r.height;
82  capture->width = selection.r.width;
83  }
84  }
85 
86  /* 4. init the capture context now that we have the capture format */
87  if (!capture->buffers) {
88  ret = ff_v4l2_context_init(capture);
89  if (ret) {
90  av_log(avctx, AV_LOG_ERROR, "can't request capture buffers\n");
91  return AVERROR(ENOMEM);
92  }
93  }
94 
95  /* 5. start the capture process */
96  ret = ff_v4l2_context_set_status(capture, VIDIOC_STREAMON);
97  if (ret) {
98  av_log(avctx, AV_LOG_DEBUG, "VIDIOC_STREAMON, on capture context\n");
99  return ret;
100  }
101 
102  return 0;
103 }
104 
106 {
107  struct v4l2_event_subscription sub;
108  V4L2Context *output = &s->output;
109  int ret;
110 
111  /**
112  * requirements
113  */
114  memset(&sub, 0, sizeof(sub));
115  sub.type = V4L2_EVENT_SOURCE_CHANGE;
116  ret = ioctl(s->fd, VIDIOC_SUBSCRIBE_EVENT, &sub);
117  if ( ret < 0) {
118  if (output->height == 0 || output->width == 0) {
120  "the v4l2 driver does not support VIDIOC_SUBSCRIBE_EVENT\n"
121  "you must provide codec_height and codec_width on input\n");
122  return ret;
123  }
124  }
125 
126  memset(&sub, 0, sizeof(sub));
127  sub.type = V4L2_EVENT_EOS;
128  ret = ioctl(s->fd, VIDIOC_SUBSCRIBE_EVENT, &sub);
129  if (ret < 0)
131  "the v4l2 driver does not support end of stream VIDIOC_SUBSCRIBE_EVENT\n");
132 
133  return 0;
134 }
135 
137 {
138  V4L2m2mContext *s = ((V4L2m2mPriv*)avctx->priv_data)->context;
139  V4L2Context *const capture = &s->capture;
140  V4L2Context *const output = &s->output;
141  AVPacket avpkt = {0};
142  int ret;
143 
144  if (s->buf_pkt.size) {
145  avpkt = s->buf_pkt;
146  memset(&s->buf_pkt, 0, sizeof(AVPacket));
147  } else {
148  ret = ff_decode_get_packet(avctx, &avpkt);
149  if (ret < 0 && ret != AVERROR_EOF)
150  return ret;
151  }
152 
153  if (s->draining)
154  goto dequeue;
155 
156  ret = ff_v4l2_context_enqueue_packet(output, &avpkt);
157  if (ret < 0) {
158  if (ret != AVERROR(EAGAIN))
159  return ret;
160 
161  s->buf_pkt = avpkt;
162  /* no input buffers available, continue dequeing */
163  }
164 
165  if (avpkt.size) {
166  ret = v4l2_try_start(avctx);
167  if (ret) {
168  av_packet_unref(&avpkt);
169 
170  /* cant recover */
171  if (ret == AVERROR(ENOMEM))
172  return ret;
173 
174  return 0;
175  }
176  }
177 
178 dequeue:
179  if (!s->buf_pkt.size)
180  av_packet_unref(&avpkt);
181  return ff_v4l2_context_dequeue_frame(capture, frame, -1);
182 }
183 
185 {
186  V4L2Context *capture, *output;
187  V4L2m2mContext *s;
188  V4L2m2mPriv *priv = avctx->priv_data;
189  int ret;
190 
191  ret = ff_v4l2_m2m_create_context(priv, &s);
192  if (ret < 0)
193  return ret;
194 
195  capture = &s->capture;
196  output = &s->output;
197 
198  /* if these dimensions are invalid (ie, 0 or too small) an event will be raised
199  * by the v4l2 driver; this event will trigger a full pipeline reconfig and
200  * the proper values will be retrieved from the kernel driver.
201  */
202  output->height = capture->height = avctx->coded_height;
203  output->width = capture->width = avctx->coded_width;
204 
205  output->av_codec_id = avctx->codec_id;
206  output->av_pix_fmt = AV_PIX_FMT_NONE;
207 
209  capture->av_pix_fmt = avctx->pix_fmt;
210 
211  s->avctx = avctx;
212  ret = ff_v4l2_m2m_codec_init(priv);
213  if (ret) {
214  av_log(avctx, AV_LOG_ERROR, "can't configure decoder\n");
215  s->self_ref = NULL;
217 
218  return ret;
219  }
220 
221  return v4l2_prepare_decoder(s);
222 }
223 
225 {
226  V4L2m2mPriv *priv = avctx->priv_data;
227  V4L2m2mContext *s = priv->context;
229  return ff_v4l2_m2m_codec_end(priv);
230 }
231 
232 #define OFFSET(x) offsetof(V4L2m2mPriv, x)
233 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_DECODING_PARAM
234 
235 static const AVOption options[] = {
237  { "num_capture_buffers", "Number of buffers in the capture context",
238  OFFSET(num_capture_buffers), AV_OPT_TYPE_INT, {.i64 = 20}, 20, INT_MAX, FLAGS },
239  { NULL},
240 };
241 
242 #define M2MDEC_CLASS(NAME) \
243  static const AVClass v4l2_m2m_ ## NAME ## _dec_class = { \
244  .class_name = #NAME "_v4l2m2m_decoder", \
245  .item_name = av_default_item_name, \
246  .option = options, \
247  .version = LIBAVUTIL_VERSION_INT, \
248  };
249 
250 #define M2MDEC(NAME, LONGNAME, CODEC, bsf_name) \
251  M2MDEC_CLASS(NAME) \
252  AVCodec ff_ ## NAME ## _v4l2m2m_decoder = { \
253  .name = #NAME "_v4l2m2m" , \
254  .long_name = NULL_IF_CONFIG_SMALL("V4L2 mem2mem " LONGNAME " decoder wrapper"), \
255  .type = AVMEDIA_TYPE_VIDEO, \
256  .id = CODEC , \
257  .priv_data_size = sizeof(V4L2m2mPriv), \
258  .priv_class = &v4l2_m2m_ ## NAME ## _dec_class, \
259  .init = v4l2_decode_init, \
260  .receive_frame = v4l2_receive_frame, \
261  .close = v4l2_decode_close, \
262  .bsfs = bsf_name, \
263  .capabilities = AV_CODEC_CAP_HARDWARE | AV_CODEC_CAP_DELAY | AV_CODEC_CAP_AVOID_PROBING, \
264  .caps_internal = FF_CODEC_CAP_SETS_PKT_DTS, \
265  .wrapper_name = "v4l2m2m", \
266  }
267 
268 M2MDEC(h264, "H.264", AV_CODEC_ID_H264, "h264_mp4toannexb");
269 M2MDEC(hevc, "HEVC", AV_CODEC_ID_HEVC, "hevc_mp4toannexb");
270 M2MDEC(mpeg1, "MPEG1", AV_CODEC_ID_MPEG1VIDEO, NULL);
271 M2MDEC(mpeg2, "MPEG2", AV_CODEC_ID_MPEG2VIDEO, NULL);
272 M2MDEC(mpeg4, "MPEG4", AV_CODEC_ID_MPEG4, NULL);
273 M2MDEC(h263, "H.263", AV_CODEC_ID_H263, NULL);
274 M2MDEC(vc1 , "VC1", AV_CODEC_ID_VC1, NULL);
275 M2MDEC(vp8, "VP8", AV_CODEC_ID_VP8, NULL);
276 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
void av_buffer_unref(AVBufferRef **buf)
Free a given reference and automatically free the buffer if there are no more references to it...
Definition: buffer.c:125
static const AVOption options[]
Definition: v4l2_m2m_dec.c:235
This structure describes decoded (raw) audio or video data.
Definition: frame.h:300
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:714
#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:722
int size
Definition: packet.h:356
#define FLAGS
Definition: v4l2_m2m_dec.c:233
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:736
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_end(V4L2m2mPriv *priv)
Releases all the codec resources if all AVBufferRefs have been returned to the ctx.
Definition: v4l2_m2m.c:336
int ff_v4l2_m2m_codec_init(V4L2m2mPriv *priv)
Probes the video nodes looking for the required codec capabilities.
Definition: v4l2_m2m.c:357
enum AVCodecID av_codec_id
AVCodecID corresponding to this buffer context.
Definition: v4l2_context.h:59
int ff_v4l2_m2m_create_context(V4L2m2mPriv *priv, V4L2m2mContext **s)
Allocate a new context and references for a V4L2 M2M instance.
Definition: v4l2_m2m.c:395
#define av_cold
Definition: attributes.h:88
AVOptions.
#define OFFSET(x)
Definition: v4l2_m2m_dec.c:232
static int v4l2_receive_frame(AVCodecContext *avctx, AVFrame *frame)
Definition: v4l2_m2m_dec.c:136
int ff_decode_get_packet(AVCodecContext *avctx, AVPacket *pkt)
Called by decoders to get the next packet for decoding.
Definition: decode.c:238
static AVFrame * frame
#define AVERROR_EOF
End of file.
Definition: error.h:55
#define av_log(a,...)
#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
V4L2m2mContext * context
Definition: v4l2_m2m.h:71
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:77
int streamon
Whether the stream has been started (VIDIOC_STREAMON has been sent).
Definition: v4l2_context.h:87
int ff_v4l2_context_enqueue_packet(V4L2Context *ctx, const AVPacket *pkt)
Enqueues a buffer to a V4L2Context from an AVPacket.
Definition: v4l2_context.c:611
#define s(width, name)
Definition: cbs_vp9.c:257
preferred ID for MPEG-1/2 video decoding
Definition: codec_id.h:51
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:572
static int v4l2_try_start(AVCodecContext *avctx)
Definition: v4l2_m2m_dec.c:37
V4L2Context capture
Definition: v4l2_m2m.h:48
Libavcodec external API header.
enum AVCodecID codec_id
Definition: avcodec.h:536
main external API structure.
Definition: avcodec.h:526
void av_packet_unref(AVPacket *pkt)
Wipe the packet.
Definition: avpacket.c:605
int ff_v4l2_context_dequeue_frame(V4L2Context *ctx, AVFrame *frame, int timeout)
Dequeues a buffer from a V4L2Context to an AVFrame.
Definition: v4l2_context.c:636
int coded_height
Definition: avcodec.h:714
#define M2MDEC(NAME, LONGNAME, CODEC, bsf_name)
Definition: v4l2_m2m_dec.c:250
static int v4l2_prepare_decoder(V4L2m2mContext *s)
Definition: v4l2_m2m_dec.c:105
AVPacket buf_pkt
Definition: v4l2_m2m.h:59
static av_cold int v4l2_decode_init(AVCodecContext *avctx)
Definition: v4l2_m2m_dec.c:184
V4L2Context output
Definition: v4l2_m2m.h:49
static av_cold int v4l2_decode_close(AVCodecContext *avctx)
Definition: v4l2_m2m_dec.c:224
common internal api header.
AVBufferRef * self_ref
Definition: v4l2_m2m.h:62
void * priv_data
Definition: avcodec.h:553
pixel format definitions
#define V4L_M2M_DEFAULT_OPTS
Definition: v4l2_m2m.h:39
AVBufferRef * context_ref
Definition: v4l2_m2m.h:72
This structure stores compressed data.
Definition: packet.h:332
enum v4l2_buf_type type
Type of this buffer context.
Definition: v4l2_context.h:47