libavcodec/v4l2_context.c
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 /*
  * V4L2 context helper functions.
  *
  * Copyright (C) 2017 Alexis Ballier <aballier@gentoo.org>
  * Copyright (C) 2017 Jorge Ramirez <jorge.ramirez-ortiz@linaro.org>
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #include <linux/videodev2.h>
 #include <sys/ioctl.h>
 #include <sys/mman.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include <poll.h>
 #include "libavcodec/avcodec.h"
 #include "libavcodec/internal.h"
 #include "v4l2_buffers.h"
 #include "v4l2_fmt.h"
 #include "v4l2_m2m.h"
 
 struct v4l2_format_update {
     uint32_t v4l2_fmt;
     int update_v4l2;
 
     enum AVPixelFormat av_fmt;
     int update_avfmt;
 };
 
 static inline V4L2m2mContext *ctx_to_m2mctx(V4L2Context *ctx)
 {
     return V4L2_TYPE_IS_OUTPUT(ctx->type) ?
         container_of(ctx, V4L2m2mContext, output) :
         container_of(ctx, V4L2m2mContext, capture);
 }
 
 static inline AVCodecContext *logger(V4L2Context *ctx)
 {
     return ctx_to_m2mctx(ctx)->avctx;
 }
 
 static inline unsigned int v4l2_get_width(struct v4l2_format *fmt)
 {
     return V4L2_TYPE_IS_MULTIPLANAR(fmt->type) ? fmt->fmt.pix_mp.width : fmt->fmt.pix.width;
 }
 
 static inline unsigned int v4l2_get_height(struct v4l2_format *fmt)
 {
     return V4L2_TYPE_IS_MULTIPLANAR(fmt->type) ? fmt->fmt.pix_mp.height : fmt->fmt.pix.height;
 }
 
 static inline unsigned int v4l2_resolution_changed(V4L2Context *ctx, struct v4l2_format *fmt2)
 {
     struct v4l2_format *fmt1 = &ctx->format;
     int ret =  V4L2_TYPE_IS_MULTIPLANAR(ctx->type) ?
         fmt1->fmt.pix_mp.width != fmt2->fmt.pix_mp.width ||
         fmt1->fmt.pix_mp.height != fmt2->fmt.pix_mp.height
         :
         fmt1->fmt.pix.width != fmt2->fmt.pix.width ||
         fmt1->fmt.pix.height != fmt2->fmt.pix.height;
 
     if (ret)
         av_log(logger(ctx), AV_LOG_DEBUG, "%s changed (%dx%d) -> (%dx%d)\n",
             ctx->name,
             v4l2_get_width(fmt1), v4l2_get_height(fmt1),
             v4l2_get_width(fmt2), v4l2_get_height(fmt2));
 
     return ret;
 }
 
 static inline int v4l2_type_supported(V4L2Context *ctx)
 {
     return ctx->type == V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE ||
         ctx->type == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE ||
         ctx->type == V4L2_BUF_TYPE_VIDEO_CAPTURE ||
         ctx->type == V4L2_BUF_TYPE_VIDEO_OUTPUT;
 }
 
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 static inline int v4l2_get_framesize_compressed(V4L2Context* ctx, int width, int height)
 {
     V4L2m2mContext *s = ctx_to_m2mctx(ctx);
     const int SZ_4K = 0x1000;
     int size;
 
     if (av_codec_is_decoder(s->avctx->codec))
         return ((width * height * 3 / 2) / 2) + 128;
 
     /* encoder */
     size = FFALIGN(height, 32) * FFALIGN(width, 32) * 3 / 2 / 2;
     return FFALIGN(size, SZ_4K);
 }
 
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 static inline void v4l2_save_to_context(V4L2Context* ctx, struct v4l2_format_update *fmt)
 {
     ctx->format.type = ctx->type;
 
     if (fmt->update_avfmt)
         ctx->av_pix_fmt = fmt->av_fmt;
 
     if (V4L2_TYPE_IS_MULTIPLANAR(ctx->type)) {
         /* update the sizes to handle the reconfiguration of the capture stream at runtime */
         ctx->format.fmt.pix_mp.height = ctx->height;
         ctx->format.fmt.pix_mp.width = ctx->width;
44188993
         if (fmt->update_v4l2) {
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             ctx->format.fmt.pix_mp.pixelformat = fmt->v4l2_fmt;
44188993
 
             /* s5p-mfc requires the user to specify a buffer size */
             ctx->format.fmt.pix_mp.plane_fmt[0].sizeimage =
                 v4l2_get_framesize_compressed(ctx, ctx->width, ctx->height);
         }
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     } else {
         ctx->format.fmt.pix.height = ctx->height;
         ctx->format.fmt.pix.width = ctx->width;
44188993
         if (fmt->update_v4l2) {
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             ctx->format.fmt.pix.pixelformat = fmt->v4l2_fmt;
44188993
 
             /* s5p-mfc requires the user to specify a buffer size */
             ctx->format.fmt.pix.sizeimage =
                 v4l2_get_framesize_compressed(ctx, ctx->width, ctx->height);
         }
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     }
 }
 
 /**
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  * returns 1 if reinit was successful, negative if it failed
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  * returns 0 if reinit was not executed
  */
 static int v4l2_handle_event(V4L2Context *ctx)
 {
     V4L2m2mContext *s = ctx_to_m2mctx(ctx);
     struct v4l2_format cap_fmt = s->capture.format;
     struct v4l2_format out_fmt = s->output.format;
     struct v4l2_event evt = { 0 };
     int full_reinit, reinit, ret;
 
     ret = ioctl(s->fd, VIDIOC_DQEVENT, &evt);
     if (ret < 0) {
         av_log(logger(ctx), AV_LOG_ERROR, "%s VIDIOC_DQEVENT\n", ctx->name);
         return 0;
     }
 
     if (evt.type != V4L2_EVENT_SOURCE_CHANGE)
         return 0;
 
     ret = ioctl(s->fd, VIDIOC_G_FMT, &out_fmt);
     if (ret) {
         av_log(logger(ctx), AV_LOG_ERROR, "%s VIDIOC_G_FMT\n", s->output.name);
         return 0;
     }
 
     ret = ioctl(s->fd, VIDIOC_G_FMT, &cap_fmt);
     if (ret) {
         av_log(logger(ctx), AV_LOG_ERROR, "%s VIDIOC_G_FMT\n", s->capture.name);
         return 0;
     }
 
     full_reinit = v4l2_resolution_changed(&s->output, &out_fmt);
     if (full_reinit) {
         s->output.height = v4l2_get_height(&out_fmt);
         s->output.width = v4l2_get_width(&out_fmt);
     }
 
     reinit = v4l2_resolution_changed(&s->capture, &cap_fmt);
     if (reinit) {
         s->capture.height = v4l2_get_height(&cap_fmt);
         s->capture.width = v4l2_get_width(&cap_fmt);
     }
 
     if (full_reinit || reinit)
         s->reinit = 1;
 
     if (full_reinit) {
         ret = ff_v4l2_m2m_codec_full_reinit(s);
         if (ret) {
             av_log(logger(ctx), AV_LOG_ERROR, "v4l2_m2m_codec_full_reinit\n");
             return -EINVAL;
         }
         goto reinit_run;
     }
 
     if (reinit) {
         ret = ff_set_dimensions(s->avctx, s->capture.width, s->capture.height);
         if (ret < 0)
             av_log(logger(ctx), AV_LOG_WARNING, "update avcodec height and width\n");
 
         ret = ff_v4l2_m2m_codec_reinit(s);
         if (ret) {
             av_log(logger(ctx), AV_LOG_ERROR, "v4l2_m2m_codec_reinit\n");
             return -EINVAL;
         }
         goto reinit_run;
     }
 
     /* dummy event received */
     return 0;
 
     /* reinit executed */
 reinit_run:
     return 1;
 }
 
 static int v4l2_stop_decode(V4L2Context *ctx)
 {
     struct v4l2_decoder_cmd cmd = {
         .cmd = V4L2_DEC_CMD_STOP,
     };
     int ret;
 
     ret = ioctl(ctx_to_m2mctx(ctx)->fd, VIDIOC_DECODER_CMD, &cmd);
     if (ret) {
         /* DECODER_CMD is optional */
         if (errno == ENOTTY)
             return ff_v4l2_context_set_status(ctx, VIDIOC_STREAMOFF);
     }
 
     return 0;
 }
 
 static int v4l2_stop_encode(V4L2Context *ctx)
 {
     struct v4l2_encoder_cmd cmd = {
         .cmd = V4L2_ENC_CMD_STOP,
     };
     int ret;
 
     ret = ioctl(ctx_to_m2mctx(ctx)->fd, VIDIOC_ENCODER_CMD, &cmd);
     if (ret) {
         /* ENCODER_CMD is optional */
         if (errno == ENOTTY)
             return ff_v4l2_context_set_status(ctx, VIDIOC_STREAMOFF);
     }
 
     return 0;
 }
 
 static V4L2Buffer* v4l2_dequeue_v4l2buf(V4L2Context *ctx, int timeout)
 {
     struct v4l2_plane planes[VIDEO_MAX_PLANES];
     struct v4l2_buffer buf = { 0 };
     V4L2Buffer* avbuf = NULL;
     struct pollfd pfd = {
         .events =  POLLIN | POLLRDNORM | POLLPRI | POLLOUT | POLLWRNORM, /* default blocking capture */
         .fd = ctx_to_m2mctx(ctx)->fd,
     };
     int ret;
 
     if (V4L2_TYPE_IS_OUTPUT(ctx->type))
         pfd.events =  POLLOUT | POLLWRNORM;
 
     for (;;) {
         ret = poll(&pfd, 1, timeout);
         if (ret > 0)
             break;
         if (errno == EINTR)
             continue;
 
         /* timeout is being used to indicate last valid bufer when draining */
         if (ctx_to_m2mctx(ctx)->draining)
             ctx->done = 1;
 
         return NULL;
     }
 
     /* 0. handle errors */
     if (pfd.revents & POLLERR) {
         av_log(logger(ctx), AV_LOG_WARNING, "%s POLLERR\n", ctx->name);
         return NULL;
     }
 
     /* 1. handle resolution changes */
     if (pfd.revents & POLLPRI) {
         ret = v4l2_handle_event(ctx);
         if (ret < 0) {
             /* if re-init failed, abort */
             ctx->done = EINVAL;
             return NULL;
         }
         if (ret) {
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             /* if re-init was successful drop the buffer (if there was one)
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              * since we had to reconfigure capture (unmap all buffers)
              */
             return NULL;
         }
     }
 
     /* 2. dequeue the buffer */
     if (pfd.revents & (POLLIN | POLLRDNORM | POLLOUT | POLLWRNORM)) {
 
         if (!V4L2_TYPE_IS_OUTPUT(ctx->type)) {
             /* there is a capture buffer ready */
             if (pfd.revents & (POLLIN | POLLRDNORM))
                 goto dequeue;
 
             /* the driver is ready to accept more input; instead of waiting for the capture
              * buffer to complete we return NULL so input can proceed (we are single threaded)
              */
             if (pfd.revents & (POLLOUT | POLLWRNORM))
                 return NULL;
         }
 
 dequeue:
         memset(&buf, 0, sizeof(buf));
         buf.memory = V4L2_MEMORY_MMAP;
         buf.type = ctx->type;
         if (V4L2_TYPE_IS_MULTIPLANAR(ctx->type)) {
             memset(planes, 0, sizeof(planes));
             buf.length = VIDEO_MAX_PLANES;
             buf.m.planes = planes;
         }
 
         ret = ioctl(ctx_to_m2mctx(ctx)->fd, VIDIOC_DQBUF, &buf);
         if (ret) {
             if (errno != EAGAIN) {
                 ctx->done = errno;
                 if (errno != EPIPE)
                     av_log(logger(ctx), AV_LOG_DEBUG, "%s VIDIOC_DQBUF, errno (%s)\n",
                         ctx->name, av_err2str(AVERROR(errno)));
             }
         } else {
             avbuf = &ctx->buffers[buf.index];
             avbuf->status = V4L2BUF_AVAILABLE;
             avbuf->buf = buf;
             if (V4L2_TYPE_IS_MULTIPLANAR(ctx->type)) {
                 memcpy(avbuf->planes, planes, sizeof(planes));
                 avbuf->buf.m.planes = avbuf->planes;
             }
         }
     }
 
     return avbuf;
 }
 
 static V4L2Buffer* v4l2_getfree_v4l2buf(V4L2Context *ctx)
 {
     int timeout = 0; /* return when no more buffers to dequeue */
     int i;
 
     /* get back as many output buffers as possible */
     if (V4L2_TYPE_IS_OUTPUT(ctx->type)) {
           do {
           } while (v4l2_dequeue_v4l2buf(ctx, timeout));
     }
 
     for (i = 0; i < ctx->num_buffers; i++) {
         if (ctx->buffers[i].status == V4L2BUF_AVAILABLE)
             return &ctx->buffers[i];
     }
 
     return NULL;
 }
 
 static int v4l2_release_buffers(V4L2Context* ctx)
 {
     struct v4l2_requestbuffers req = {
         .memory = V4L2_MEMORY_MMAP,
         .type = ctx->type,
         .count = 0, /* 0 -> unmaps buffers from the driver */
     };
     int i, j;
 
     for (i = 0; i < ctx->num_buffers; i++) {
         V4L2Buffer *buffer = &ctx->buffers[i];
 
         for (j = 0; j < buffer->num_planes; j++) {
             struct V4L2Plane_info *p = &buffer->plane_info[j];
             if (p->mm_addr && p->length)
                 if (munmap(p->mm_addr, p->length) < 0)
                     av_log(logger(ctx), AV_LOG_ERROR, "%s unmap plane (%s))\n", ctx->name, av_err2str(AVERROR(errno)));
         }
     }
 
     return ioctl(ctx_to_m2mctx(ctx)->fd, VIDIOC_REQBUFS, &req);
 }
 
 static inline int v4l2_try_raw_format(V4L2Context* ctx, enum AVPixelFormat pixfmt)
 {
     struct v4l2_format *fmt = &ctx->format;
     uint32_t v4l2_fmt;
     int ret;
 
     v4l2_fmt = ff_v4l2_format_avfmt_to_v4l2(pixfmt);
     if (!v4l2_fmt)
         return AVERROR(EINVAL);
 
     if (V4L2_TYPE_IS_MULTIPLANAR(ctx->type))
         fmt->fmt.pix_mp.pixelformat = v4l2_fmt;
     else
         fmt->fmt.pix.pixelformat = v4l2_fmt;
 
     fmt->type = ctx->type;
 
     ret = ioctl(ctx_to_m2mctx(ctx)->fd, VIDIOC_TRY_FMT, fmt);
     if (ret)
         return AVERROR(EINVAL);
 
     return 0;
 }
 
 static int v4l2_get_raw_format(V4L2Context* ctx, enum AVPixelFormat *p)
 {
     enum AVPixelFormat pixfmt = ctx->av_pix_fmt;
     struct v4l2_fmtdesc fdesc;
     int ret;
 
     memset(&fdesc, 0, sizeof(fdesc));
     fdesc.type = ctx->type;
 
     if (pixfmt != AV_PIX_FMT_NONE) {
         ret = v4l2_try_raw_format(ctx, pixfmt);
         if (ret)
             pixfmt = AV_PIX_FMT_NONE;
         else
             return 0;
     }
 
     for (;;) {
         ret = ioctl(ctx_to_m2mctx(ctx)->fd, VIDIOC_ENUM_FMT, &fdesc);
         if (ret)
             return AVERROR(EINVAL);
 
         pixfmt = ff_v4l2_format_v4l2_to_avfmt(fdesc.pixelformat, AV_CODEC_ID_RAWVIDEO);
         ret = v4l2_try_raw_format(ctx, pixfmt);
         if (ret){
             fdesc.index++;
             continue;
         }
 
         *p = pixfmt;
 
         return 0;
     }
 
     return AVERROR(EINVAL);
 }
 
 static int v4l2_get_coded_format(V4L2Context* ctx, uint32_t *p)
 {
     struct v4l2_fmtdesc fdesc;
     uint32_t v4l2_fmt;
     int ret;
 
     /* translate to a valid v4l2 format */
     v4l2_fmt = ff_v4l2_format_avcodec_to_v4l2(ctx->av_codec_id);
     if (!v4l2_fmt)
         return AVERROR(EINVAL);
 
     /* check if the driver supports this format */
     memset(&fdesc, 0, sizeof(fdesc));
     fdesc.type = ctx->type;
 
     for (;;) {
         ret = ioctl(ctx_to_m2mctx(ctx)->fd, VIDIOC_ENUM_FMT, &fdesc);
         if (ret)
             return AVERROR(EINVAL);
 
         if (fdesc.pixelformat == v4l2_fmt)
             break;
 
         fdesc.index++;
     }
 
     *p = v4l2_fmt;
 
     return 0;
 }
 
  /*****************************************************************************
   *
   *             V4L2 Context Interface
   *
   *****************************************************************************/
 
 int ff_v4l2_context_set_status(V4L2Context* ctx, int cmd)
 {
     int type = ctx->type;
     int ret;
 
     ret = ioctl(ctx_to_m2mctx(ctx)->fd, cmd, &type);
     if (ret < 0)
         return AVERROR(errno);
 
     ctx->streamon = (cmd == VIDIOC_STREAMON);
 
     return 0;
 }
 
 int ff_v4l2_context_enqueue_frame(V4L2Context* ctx, const AVFrame* frame)
 {
     V4L2m2mContext *s = ctx_to_m2mctx(ctx);
     V4L2Buffer* avbuf;
     int ret;
 
     if (!frame) {
         ret = v4l2_stop_encode(ctx);
         if (ret)
             av_log(logger(ctx), AV_LOG_ERROR, "%s stop_encode\n", ctx->name);
         s->draining= 1;
         return 0;
     }
 
     avbuf = v4l2_getfree_v4l2buf(ctx);
     if (!avbuf)
         return AVERROR(ENOMEM);
 
     ret = ff_v4l2_buffer_avframe_to_buf(frame, avbuf);
     if (ret)
         return ret;
 
     return ff_v4l2_buffer_enqueue(avbuf);
 }
 
 int ff_v4l2_context_enqueue_packet(V4L2Context* ctx, const AVPacket* pkt)
 {
     V4L2m2mContext *s = ctx_to_m2mctx(ctx);
     V4L2Buffer* avbuf;
     int ret;
 
     if (!pkt->size) {
         ret = v4l2_stop_decode(ctx);
         if (ret)
             av_log(logger(ctx), AV_LOG_ERROR, "%s stop_decode\n", ctx->name);
         s->draining = 1;
         return 0;
     }
 
     avbuf = v4l2_getfree_v4l2buf(ctx);
     if (!avbuf)
         return AVERROR(ENOMEM);
 
     ret = ff_v4l2_buffer_avpkt_to_buf(pkt, avbuf);
     if (ret)
         return ret;
 
     return ff_v4l2_buffer_enqueue(avbuf);
 }
 
 int ff_v4l2_context_dequeue_frame(V4L2Context* ctx, AVFrame* frame)
 {
     V4L2Buffer* avbuf = NULL;
 
     /* if we are draining, we are no longer inputing data, therefore enable a
      * timeout so we can dequeue and flag the last valid buffer.
      *
      * blocks until:
      *  1. decoded frame available
      *  2. an input buffer is ready to be dequeued
      */
     avbuf = v4l2_dequeue_v4l2buf(ctx, ctx_to_m2mctx(ctx)->draining ? 200 : -1);
     if (!avbuf) {
         if (ctx->done)
             return AVERROR_EOF;
 
         return AVERROR(EAGAIN);
     }
 
     return ff_v4l2_buffer_buf_to_avframe(frame, avbuf);
 }
 
 int ff_v4l2_context_dequeue_packet(V4L2Context* ctx, AVPacket* pkt)
 {
     V4L2Buffer* avbuf = NULL;
 
     /* if we are draining, we are no longer inputing data, therefore enable a
      * timeout so we can dequeue and flag the last valid buffer.
      *
      * blocks until:
      *  1. encoded packet available
      *  2. an input buffer ready to be dequeued
      */
     avbuf = v4l2_dequeue_v4l2buf(ctx, ctx_to_m2mctx(ctx)->draining ? 200 : -1);
     if (!avbuf) {
         if (ctx->done)
             return AVERROR_EOF;
 
         return AVERROR(EAGAIN);
     }
 
     return ff_v4l2_buffer_buf_to_avpkt(pkt, avbuf);
 }
 
 int ff_v4l2_context_get_format(V4L2Context* ctx)
 {
     struct v4l2_format_update fmt = { 0 };
     int ret;
 
     if  (ctx->av_codec_id == AV_CODEC_ID_RAWVIDEO) {
         ret = v4l2_get_raw_format(ctx, &fmt.av_fmt);
         if (ret)
             return ret;
 
         fmt.update_avfmt = 1;
         v4l2_save_to_context(ctx, &fmt);
 
         /* format has been tried already */
         return ret;
     }
 
     ret = v4l2_get_coded_format(ctx, &fmt.v4l2_fmt);
     if (ret)
         return ret;
 
     fmt.update_v4l2 = 1;
     v4l2_save_to_context(ctx, &fmt);
 
     return ioctl(ctx_to_m2mctx(ctx)->fd, VIDIOC_TRY_FMT, &ctx->format);
 }
 
 int ff_v4l2_context_set_format(V4L2Context* ctx)
 {
     return ioctl(ctx_to_m2mctx(ctx)->fd, VIDIOC_S_FMT, &ctx->format);
 }
 
 void ff_v4l2_context_release(V4L2Context* ctx)
 {
     int ret;
 
     if (!ctx->buffers)
         return;
 
     ret = v4l2_release_buffers(ctx);
     if (ret)
         av_log(logger(ctx), AV_LOG_WARNING, "V4L2 failed to unmap the %s buffers\n", ctx->name);
 
     av_free(ctx->buffers);
     ctx->buffers = NULL;
 }
 
 int ff_v4l2_context_init(V4L2Context* ctx)
 {
     V4L2m2mContext *s = ctx_to_m2mctx(ctx);
     struct v4l2_requestbuffers req;
     int ret, i;
 
     if (!v4l2_type_supported(ctx)) {
         av_log(logger(ctx), AV_LOG_ERROR, "type %i not supported\n", ctx->type);
         return AVERROR_PATCHWELCOME;
     }
 
     ret = ioctl(s->fd, VIDIOC_G_FMT, &ctx->format);
     if (ret)
         av_log(logger(ctx), AV_LOG_ERROR, "%s VIDIOC_G_FMT failed\n", ctx->name);
 
     memset(&req, 0, sizeof(req));
     req.count = ctx->num_buffers;
     req.memory = V4L2_MEMORY_MMAP;
     req.type = ctx->type;
     ret = ioctl(s->fd, VIDIOC_REQBUFS, &req);
     if (ret < 0)
         return AVERROR(errno);
 
     ctx->num_buffers = req.count;
     ctx->buffers = av_mallocz(ctx->num_buffers * sizeof(V4L2Buffer));
     if (!ctx->buffers) {
             av_log(logger(ctx), AV_LOG_ERROR, "%s malloc enomem\n", ctx->name);
             return AVERROR(ENOMEM);
     }
 
     for (i = 0; i < req.count; i++) {
         ctx->buffers[i].context = ctx;
         ret = ff_v4l2_buffer_initialize(&ctx->buffers[i], i);
         if (ret < 0) {
             av_log(logger(ctx), AV_LOG_ERROR, "%s buffer initialization (%s)\n", ctx->name, av_err2str(ret));
             av_free(ctx->buffers);
             return ret;
         }
     }
 
     av_log(logger(ctx), AV_LOG_DEBUG, "%s: %s %02d buffers initialized: %04ux%04u, sizeimage %08u, bytesperline %08u\n", ctx->name,
         V4L2_TYPE_IS_MULTIPLANAR(ctx->type) ? av_fourcc2str(ctx->format.fmt.pix_mp.pixelformat) : av_fourcc2str(ctx->format.fmt.pix.pixelformat),
         req.count,
         v4l2_get_width(&ctx->format),
         v4l2_get_height(&ctx->format),
         V4L2_TYPE_IS_MULTIPLANAR(ctx->type) ? ctx->format.fmt.pix_mp.plane_fmt[0].sizeimage : ctx->format.fmt.pix.sizeimage,
         V4L2_TYPE_IS_MULTIPLANAR(ctx->type) ? ctx->format.fmt.pix_mp.plane_fmt[0].bytesperline : ctx->format.fmt.pix.bytesperline);
 
     return 0;
 }