[FFmpeg-devel] [PATCH 2/2] libavcodec/v4l2: use libdrm
Zhao Zhili
quinkblack at foxmail.com
Mon Dec 16 05:15:43 EET 2024
> On Dec 15, 2024, at 12:14, Scott Theisen <scott.the.elm at gmail.com> wrote:
>
> Based on patches by Lukas Rusak from
> https://github.com/lrusak/FFmpeg/commits/v4l2-drmprime-v4
>
> libavcodec: v4l2m2m: output AVDRMFrameDescriptor
> https://github.com/lrusak/FFmpeg/commit/2cb8052ac65a56d8a3f347a1e6f12d4449a5a614
>
> libavcodec: v4l2m2m: depends on libdrm
> https://github.com/lrusak/FFmpeg/commit/ab4cf3e6fb37cffdebccca52e36a7b2deb7e729f
>
> libavcodec: v4l2m2m: set format_modifier to DRM_FORMAT_MOD_LINEAR
> https://github.com/lrusak/FFmpeg/commit/9438a6efa29c7c7ec80c39c9b013b9a12d7b5f33
>
> libavcodec: v4l2m2m: only mmap the buffer when it is output type and drm prime is used
> https://github.com/lrusak/FFmpeg/commit/093656607863e47630de2d1cfcf0ac8e4b93a69e
>
> libavcodec: v4l2m2m: allow using software pixel formats
> https://github.com/lrusak/FFmpeg/commit/8405b573e83838e6b2fea99825fbef32ee9f7767
>
> libavcodec: v4l2m2m: implement hwcontext
> https://github.com/lrusak/FFmpeg/commit/b2c1f1eb39b54bf034497a7f2a7f23855d0a7cde
>
> libavcodec: v4l2m2m: implement flush
> https://github.com/lrusak/FFmpeg/commit/e793ef82727d6d6f55c40844463d476e7e84efad
>
> Originally added to MythTV in:
> FFmpeg: Patch FFmpeg for V4L2 codecs DRM PRIME support
> https://github.com/MythTV/mythtv/commit/cc7572f9b26189ad5d5d504c05f08e53e4e61b54
>
> FFmpeg: Re-apply v4l2 memory to memory DRM_PRIME support
> https://github.com/MythTV/mythtv/commit/1c942720591b5b7820abe9ed0d805afabbdffe3c
>
> modified in:
> V4L2 Codecs: Fix lockup when seeking
> https://github.com/MythTV/mythtv/commit/fdc0645aba9a9ad373888bd62ebcbc83a3feb7e5
>
> v4l2_buffers: Add some libdrm ifdef's
> https://github.com/MythTV/mythtv/commit/336df1067abfa4fe7cf611541e5b6f3561fc81a2
>
> !!!!
> NB: libavcodec/v4l2_m2m_dec.c: v4l2_decode_init(): I'm returning -1
> since I don't know what error code I should use.
>
> Note also Lucas Rusak's v5 series:
> closer diff to current state, otherwise unchanged
> libavcodec: v4l2m2m: output AVDRMFrameDescriptor
> https://github.com/lrusak/FFmpeg/commit/c6b85ed30f06ea99513b13cc768a922ebe4d68c2
>
> new option:
> libavcodec: v4l2m2m: add option to specify pixel format used by the decoder
> https://github.com/lrusak/FFmpeg/commit/ffc4419f456c00ab71cf93f792b0473c6de14e64
>
> additional code vs v4
> libavcodec: v4l2m2m: implement flush
> https://github.com/lrusak/FFmpeg/commit/8595d06d4909bbec0aa14625fcfc869c6bcef696
> ---
> configure | 1 +
> libavcodec/v4l2_buffers.c | 206 +++++++++++++++++++++++++++++++++++---
> libavcodec/v4l2_buffers.h | 4 +
> libavcodec/v4l2_context.c | 43 +++++++-
> libavcodec/v4l2_context.h | 2 +
> libavcodec/v4l2_m2m.h | 5 +
> libavcodec/v4l2_m2m_dec.c | 62 ++++++++++++
> 7 files changed, 305 insertions(+), 18 deletions(-)
>
> diff --git a/configure b/configure
> index bf55ba67fa..5f02cf3b51 100755
> --- a/configure
> +++ b/configure
> @@ -3770,6 +3770,7 @@ sndio_indev_deps="sndio"
> sndio_outdev_deps="sndio"
> v4l2_indev_deps_any="linux_videodev2_h sys_videoio_h"
> v4l2_indev_suggest="libv4l2"
> +v4l2_outdev_deps="libdrm"
Why v4l2_outdev when the patch is for libavcodec?
> v4l2_outdev_deps_any="linux_videodev2_h sys_videoio_h"
> v4l2_outdev_suggest="libv4l2"
> vfwcap_indev_deps="vfw32 vfwcap_defines"
> diff --git a/libavcodec/v4l2_buffers.c b/libavcodec/v4l2_buffers.c
> index 56a8f0825c..1a1a29c4e6 100644
> --- a/libavcodec/v4l2_buffers.c
> +++ b/libavcodec/v4l2_buffers.c
> @@ -21,6 +21,10 @@
> * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
> */
>
> +#include "config.h"
> +#if CONFIG_LIBDRM
> +#include <drm_fourcc.h>
> +#endif
> #include <linux/videodev2.h>
> #include <sys/ioctl.h>
> #include <sys/mman.h>
> @@ -29,6 +33,8 @@
> #include <poll.h>
> #include "libavcodec/avcodec.h"
> #include "libavutil/pixdesc.h"
> +#include "libavutil/hwcontext.h"
> +#include "libavutil/buffer.h"
> #include "refstruct.h"
> #include "v4l2_context.h"
> #include "v4l2_buffers.h"
> @@ -247,6 +253,80 @@ FF_ENABLE_DEPRECATION_WARNINGS
> }
> }
>
> +#if CONFIG_LIBDRM
> +static uint8_t * v4l2_get_drm_frame(V4L2Buffer *avbuf)
> +{
> + AVDRMFrameDescriptor *drm_desc = &avbuf->drm_frame;
> + AVDRMLayerDescriptor *layer;
> +
> + /* fill the DRM frame descriptor */
> + drm_desc->nb_objects = avbuf->num_planes;
> + drm_desc->nb_layers = 1;
> +
> + layer = &drm_desc->layers[0];
> + layer->nb_planes = avbuf->num_planes;
> +
> + for (int i = 0; i < avbuf->num_planes; i++) {
> + layer->planes[i].object_index = i;
> + layer->planes[i].offset = 0;
> + layer->planes[i].pitch = avbuf->plane_info[i].bytesperline;
> + }
> +
> + switch (avbuf->context->av_pix_fmt) {
> + case AV_PIX_FMT_YUYV422:
> +
> + layer->format = DRM_FORMAT_YUYV;
> + layer->nb_planes = 1;
> +
> + break;
> +
> + case AV_PIX_FMT_NV12:
> + case AV_PIX_FMT_NV21:
> +
> + layer->format = avbuf->context->av_pix_fmt == AV_PIX_FMT_NV12 ?
> + DRM_FORMAT_NV12 : DRM_FORMAT_NV21;
> +
> + if (avbuf->num_planes > 1)
> + break;
> +
> + layer->nb_planes = 2;
> +
> + layer->planes[1].object_index = 0;
> + layer->planes[1].offset = avbuf->plane_info[0].bytesperline *
> + avbuf->context->format.fmt.pix.height;
> + layer->planes[1].pitch = avbuf->plane_info[0].bytesperline;
> + break;
> +
> + case AV_PIX_FMT_YUV420P:
> +
> + layer->format = DRM_FORMAT_YUV420;
> +
> + if (avbuf->num_planes > 1)
> + break;
> +
> + layer->nb_planes = 3;
> +
> + layer->planes[1].object_index = 0;
> + layer->planes[1].offset = avbuf->plane_info[0].bytesperline *
> + avbuf->context->format.fmt.pix.height;
> + layer->planes[1].pitch = avbuf->plane_info[0].bytesperline >> 1;
> +
> + layer->planes[2].object_index = 0;
> + layer->planes[2].offset = layer->planes[1].offset +
> + ((avbuf->plane_info[0].bytesperline *
> + avbuf->context->format.fmt.pix.height) >> 2);
> + layer->planes[2].pitch = avbuf->plane_info[0].bytesperline >> 1;
> + break;
> +
> + default:
> + drm_desc->nb_layers = 0;
> + break;
> + }
> +
> + return (uint8_t *) drm_desc;
> +}
> +#endif
> +
> static void v4l2_free_buffer(void *opaque, uint8_t *unused)
> {
> V4L2Buffer* avbuf = opaque;
> @@ -271,6 +351,40 @@ static void v4l2_free_buffer(void *opaque, uint8_t *unused)
> }
> }
>
> +#if CONFIG_LIBDRM
> +static int v4l2_buffer_export_drm(V4L2Buffer* avbuf)
> +{
> + struct v4l2_exportbuffer expbuf;
> + int i, ret;
> +
> + for (i = 0; i < avbuf->num_planes; i++) {
> + memset(&expbuf, 0, sizeof(expbuf));
> +
> + expbuf.index = avbuf->buf.index;
> + expbuf.type = avbuf->buf.type;
> + expbuf.plane = i;
> +
> + ret = ioctl(buf_to_m2mctx(avbuf)->fd, VIDIOC_EXPBUF, &expbuf);
> + if (ret < 0)
> + return AVERROR(errno);
> +
> + if (V4L2_TYPE_IS_MULTIPLANAR(avbuf->buf.type)) {
> + /* drm frame */
> + avbuf->drm_frame.objects[i].size = avbuf->buf.m.planes[i].length;
> + avbuf->drm_frame.objects[i].fd = expbuf.fd;
> + avbuf->drm_frame.objects[i].format_modifier = DRM_FORMAT_MOD_LINEAR;
> + } else {
> + /* drm frame */
> + avbuf->drm_frame.objects[0].size = avbuf->buf.length;
> + avbuf->drm_frame.objects[0].fd = expbuf.fd;
> + avbuf->drm_frame.objects[0].format_modifier = DRM_FORMAT_MOD_LINEAR;
> + }
> + }
> +
> + return 0;
> +}
> +#endif
> +
> static int v4l2_buf_increase_ref(V4L2Buffer *in)
> {
> V4L2m2mContext *s = buf_to_m2mctx(in);
> @@ -289,6 +403,26 @@ static int v4l2_buf_increase_ref(V4L2Buffer *in)
> return 0;
> }
>
> +#if CONFIG_LIBDRM
> +static int v4l2_buf_to_bufref_drm(V4L2Buffer *in, AVBufferRef **buf)
> +{
> + int ret;
> +
> + *buf = av_buffer_create((uint8_t *) &in->drm_frame,
> + sizeof(in->drm_frame),
> + v4l2_free_buffer,
> + in, AV_BUFFER_FLAG_READONLY);
> + if (!*buf)
> + return AVERROR(ENOMEM);
> +
> + ret = v4l2_buf_increase_ref(in);
> + if (ret)
> + av_buffer_unref(buf);
> +
> + return ret;
> +}
> +#endif
> +
> static int v4l2_buf_to_bufref(V4L2Buffer *in, int plane, AVBufferRef **buf)
> {
> int ret;
> @@ -458,9 +592,22 @@ int ff_v4l2_buffer_buf_to_avframe(AVFrame *frame, V4L2Buffer *avbuf)
> av_frame_unref(frame);
>
> /* 1. get references to the actual data */
> - ret = v4l2_buffer_buf_to_swframe(frame, avbuf);
> - if (ret)
> - return ret;
> + if (buf_to_m2mctx(avbuf)->output_drm) {
> +#if CONFIG_LIBDRM
> + /* 1. get references to the actual data */
> + ret = v4l2_buf_to_bufref_drm(avbuf, &frame->buf[0]);
> + if (ret)
> + return ret;
> +
> + frame->data[0] = (uint8_t *) v4l2_get_drm_frame(avbuf);
> + frame->format = AV_PIX_FMT_DRM_PRIME;
> + frame->hw_frames_ctx = av_buffer_ref(avbuf->context->frames_ref);
> +#endif
> + } else {
> + ret = v4l2_buffer_buf_to_swframe(frame, avbuf);
> + if (ret)
> + return ret;
> + }
>
> /* 2. get frame information */
> if (avbuf->buf.flags & V4L2_BUF_FLAG_KEYFRAME)
> @@ -537,6 +684,27 @@ int ff_v4l2_buffer_initialize(V4L2Buffer* avbuf, int index)
> avbuf->buf.type = ctx->type;
> avbuf->buf.index = index;
>
> + if (buf_to_m2mctx(avbuf)->output_drm) {
> + AVHWFramesContext *hwframes;
> +
> + av_buffer_unref(&ctx->frames_ref);
> +
> + ctx->frames_ref = av_hwframe_ctx_alloc(buf_to_m2mctx(avbuf)->device_ref);
> + if (!ctx->frames_ref) {
> + ret = AVERROR(ENOMEM);
> + return ret;
> + }
> +
> + hwframes = (AVHWFramesContext*)ctx->frames_ref->data;
> + hwframes->format = AV_PIX_FMT_DRM_PRIME;
> + hwframes->sw_format = ctx->av_pix_fmt;
> + hwframes->width = ctx->width;
> + hwframes->height = ctx->height;
> + ret = av_hwframe_ctx_init(ctx->frames_ref);
> + if (ret < 0)
> + return ret;
> + }
> +
> if (V4L2_TYPE_IS_MULTIPLANAR(ctx->type)) {
> avbuf->buf.length = VIDEO_MAX_PLANES;
> avbuf->buf.m.planes = avbuf->planes;
> @@ -564,14 +732,20 @@ int ff_v4l2_buffer_initialize(V4L2Buffer* avbuf, int index)
>
> if (V4L2_TYPE_IS_MULTIPLANAR(ctx->type)) {
> avbuf->plane_info[i].length = avbuf->buf.m.planes[i].length;
> - avbuf->plane_info[i].mm_addr = mmap(NULL, avbuf->buf.m.planes[i].length,
> - PROT_READ | PROT_WRITE, MAP_SHARED,
> - buf_to_m2mctx(avbuf)->fd, avbuf->buf.m.planes[i].m.mem_offset);
> +
> + if (V4L2_TYPE_IS_OUTPUT(ctx->type) || !buf_to_m2mctx(avbuf)->output_drm) {
> + avbuf->plane_info[i].mm_addr = mmap(NULL, avbuf->buf.m.planes[i].length,
> + PROT_READ | PROT_WRITE, MAP_SHARED,
> + buf_to_m2mctx(avbuf)->fd, avbuf->buf.m.planes[i].m.mem_offset);
> + }
> } else {
> avbuf->plane_info[i].length = avbuf->buf.length;
> - avbuf->plane_info[i].mm_addr = mmap(NULL, avbuf->buf.length,
> - PROT_READ | PROT_WRITE, MAP_SHARED,
> - buf_to_m2mctx(avbuf)->fd, avbuf->buf.m.offset);
> +
> + if (V4L2_TYPE_IS_OUTPUT(ctx->type) || !buf_to_m2mctx(avbuf)->output_drm) {
> + avbuf->plane_info[i].mm_addr = mmap(NULL, avbuf->buf.length,
> + PROT_READ | PROT_WRITE, MAP_SHARED,
> + buf_to_m2mctx(avbuf)->fd, avbuf->buf.m.offset);
> + }
> }
>
> if (avbuf->plane_info[i].mm_addr == MAP_FAILED)
> @@ -580,18 +754,24 @@ int ff_v4l2_buffer_initialize(V4L2Buffer* avbuf, int index)
>
> avbuf->status = V4L2BUF_AVAILABLE;
>
> - if (V4L2_TYPE_IS_OUTPUT(ctx->type))
> - return 0;
> -
> if (V4L2_TYPE_IS_MULTIPLANAR(ctx->type)) {
> avbuf->buf.m.planes = avbuf->planes;
> avbuf->buf.length = avbuf->num_planes;
> -
> } else {
> avbuf->buf.bytesused = avbuf->planes[0].bytesused;
> avbuf->buf.length = avbuf->planes[0].length;
> }
>
> + if (V4L2_TYPE_IS_OUTPUT(ctx->type))
> + return 0;
> +
> +#if CONFIG_LIBDRM
> + if (buf_to_m2mctx(avbuf)->output_drm) {
> + ret = v4l2_buffer_export_drm(avbuf);
> + if (ret)
> + return ret;
> + }
> +#endif
> return ff_v4l2_buffer_enqueue(avbuf);
> }
>
> diff --git a/libavcodec/v4l2_buffers.h b/libavcodec/v4l2_buffers.h
> index e35b161309..964e037b9d 100644
> --- a/libavcodec/v4l2_buffers.h
> +++ b/libavcodec/v4l2_buffers.h
> @@ -28,6 +28,7 @@
> #include <stddef.h>
> #include <linux/videodev2.h>
>
> +#include "libavutil/hwcontext_drm.h"
> #include "libavutil/frame.h"
> #include "packet.h"
>
> @@ -44,6 +45,9 @@ typedef struct V4L2Buffer {
> /* each buffer needs to have a reference to its context */
> struct V4L2Context *context;
>
> + /* DRM descriptor */
> + AVDRMFrameDescriptor drm_frame;
> +
> /* This object is refcounted per-plane, so we need to keep track
> * of how many context-refs we are holding.
> * This pointer is a RefStruct reference. */
> diff --git a/libavcodec/v4l2_context.c b/libavcodec/v4l2_context.c
> index be1df3785b..e9c37f05cd 100644
> --- a/libavcodec/v4l2_context.c
> +++ b/libavcodec/v4l2_context.c
> @@ -290,8 +290,8 @@ static V4L2Buffer* v4l2_dequeue_v4l2buf(V4L2Context *ctx, int timeout)
> "packets/frames.\n");
> }
>
> - /* if we are draining and there are no more capture buffers queued in the driver we are done */
> - if (!V4L2_TYPE_IS_OUTPUT(ctx->type) && ctx_to_m2mctx(ctx)->draining) {
> + /* if there are no more capture buffers queued in the driver, skip polling */
> + if (!V4L2_TYPE_IS_OUTPUT(ctx->type)) {
> for (i = 0; i < ctx->num_buffers; i++) {
> /* capture buffer initialization happens during decode hence
> * detection happens at runtime
> @@ -302,7 +302,9 @@ static V4L2Buffer* v4l2_dequeue_v4l2buf(V4L2Context *ctx, int timeout)
> if (ctx->buffers[i].status == V4L2BUF_IN_DRIVER)
> goto start;
> }
> - ctx->done = 1;
> + /* if we were waiting to drain, all done! */
> + if (ctx_to_m2mctx(ctx)->draining)
> + ctx->done = 1;
> return NULL;
> }
>
> @@ -448,20 +450,51 @@ static int v4l2_release_buffers(V4L2Context* ctx)
> .type = ctx->type,
> .count = 0, /* 0 -> unmaps buffers from the driver */
> };
> - int i, j;
> + int ret, 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 (V4L2_TYPE_IS_OUTPUT(ctx->type)) {
> + /* output buffers are not EXPORTED */
> + goto unmap;
> + }
> +
> + if (ctx_to_m2mctx(ctx)->output_drm) {
> + /* use the DRM frame to close */
> + if (buffer->drm_frame.objects[j].fd >= 0) {
> + if (close(buffer->drm_frame.objects[j].fd) < 0) {
> + av_log(logger(ctx), AV_LOG_ERROR, "%s close drm fd "
> + "[buffer=%2d, plane=%d, fd=%2d] - %s \n",
> + ctx->name, i, j, buffer->drm_frame.objects[j].fd,
> + av_err2str(AVERROR(errno)));
> + }
> + }
> + }
> +unmap:
> 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);
> + ret = ioctl(ctx_to_m2mctx(ctx)->fd, VIDIOC_REQBUFS, &req);
> + if (ret < 0) {
> + av_log(logger(ctx), AV_LOG_ERROR, "release all %s buffers (%s)\n",
> + ctx->name, av_err2str(AVERROR(errno)));
> +
> + if (ctx_to_m2mctx(ctx)->output_drm)
> + av_log(logger(ctx), AV_LOG_ERROR,
> + "Make sure the DRM client releases all FB/GEM objects before closing the codec (ie):\n"
> + "for all buffers: \n"
> + " 1. drmModeRmFB(..)\n"
> + " 2. drmIoctl(.., DRM_IOCTL_GEM_CLOSE,... )\n");
> + }
> +
> + return ret;
> }
>
> static inline int v4l2_try_raw_format(V4L2Context* ctx, enum AVPixelFormat pixfmt)
> diff --git a/libavcodec/v4l2_context.h b/libavcodec/v4l2_context.h
> index 6f7460c89a..02fbb6eec3 100644
> --- a/libavcodec/v4l2_context.h
> +++ b/libavcodec/v4l2_context.h
> @@ -93,6 +93,8 @@ typedef struct V4L2Context {
> */
> int done;
>
> + AVBufferRef *frames_ref;
> +
> } V4L2Context;
>
> /**
> diff --git a/libavcodec/v4l2_m2m.h b/libavcodec/v4l2_m2m.h
> index 4ba33dc335..47dfe0905f 100644
> --- a/libavcodec/v4l2_m2m.h
> +++ b/libavcodec/v4l2_m2m.h
> @@ -66,6 +66,11 @@ typedef struct V4L2m2mContext {
>
> /* reference back to V4L2m2mPriv */
> void *priv;
> +
> + AVBufferRef *device_ref;
> +
> + /* generate DRM frames */
> + int output_drm;
> } V4L2m2mContext;
>
> typedef struct V4L2m2mPriv {
> diff --git a/libavcodec/v4l2_m2m_dec.c b/libavcodec/v4l2_m2m_dec.c
> index aa2d759e1e..cfeee7f2fb 100644
> --- a/libavcodec/v4l2_m2m_dec.c
> +++ b/libavcodec/v4l2_m2m_dec.c
> @@ -23,12 +23,17 @@
>
> #include <linux/videodev2.h>
> #include <sys/ioctl.h>
> +
> +#include "libavutil/hwcontext.h"
> +#include "libavutil/hwcontext_drm.h"
> #include "libavutil/pixfmt.h"
> #include "libavutil/pixdesc.h"
> #include "libavutil/opt.h"
> #include "libavcodec/avcodec.h"
> #include "codec_internal.h"
> #include "libavcodec/decode.h"
> +#include "libavcodec/internal.h"
> +#include "libavcodec/hwconfig.h"
>
> #include "v4l2_context.h"
> #include "v4l2_m2m.h"
> @@ -205,7 +210,44 @@ static av_cold int v4l2_decode_init(AVCodecContext *avctx)
> capture->av_codec_id = AV_CODEC_ID_RAWVIDEO;
> capture->av_pix_fmt = avctx->pix_fmt;
>
> + /* the client requests the codec to generate DRM frames:
> + * - data[0] will therefore point to the returned AVDRMFrameDescriptor
> + * check the ff_v4l2_buffer_to_avframe conversion function.
> + * - the DRM frame format is passed in the DRM frame descriptor layer.
> + * check the v4l2_get_drm_frame function.
> + */
> + {
> + const enum AVPixelFormat *pix_fmts = NULL;
> + int num_pix_fmts = 0;
> + ret = avcodec_get_supported_config(avctx, NULL, AV_CODEC_CONFIG_PIX_FORMAT,
> + 0, (const void **) &pix_fmts, &num_pix_fmts);
I don’t think here is the meant use case for avcodec_get_supported_config.
Specify available pixel format directly in pix_fmts.
> + if (ret < 0)
> + return ret;
> + if (pix_fmts == NULL || num_pix_fmts < 1)
> + return -1;
There is no which error code to use issue after remove avcodec_get_supported_config.
> + switch (ff_get_format(avctx, pix_fmts)) {
> + case AV_PIX_FMT_DRM_PRIME:
> + s->output_drm = 1;
> + break;
> + case AV_PIX_FMT_NONE:
> + return 0;
> + break;
Why return 0 for AV_PIX_FMT_NONE? It’s suspicious.
‘break’ can be removed.
> + default:
> + break;
> + }
> + }
> +
> + s->device_ref = av_hwdevice_ctx_alloc(AV_HWDEVICE_TYPE_DRM);
> + if (!s->device_ref) {
> + ret = AVERROR(ENOMEM);
> + return ret;
> + }
I’m not sure whether there is use case to let user specify device?
> +
> s->avctx = avctx;
> + ret = av_hwdevice_ctx_init(s->device_ref);
> + if (ret < 0)
> + return ret;
> +
> ret = ff_v4l2_m2m_codec_init(priv);
> if (ret) {
> av_log(avctx, AV_LOG_ERROR, "can't configure decoder\n");
> @@ -220,6 +262,16 @@ static av_cold int v4l2_decode_close(AVCodecContext *avctx)
> return ff_v4l2_m2m_codec_end(avctx->priv_data);
> }
>
> +static void v4l2_flush(AVCodecContext *avctx)
> +{
> + V4L2m2mPriv *priv = avctx->priv_data;
> + V4L2m2mContext* s = priv->context;
> +
> + /* wait for pending buffer references */
> + if (atomic_load(&s->refcount))
> + while(sem_wait(&s->refsync) == -1 && errno == EINTR);
> +}
Does refcount depends on users behavior like holding a frame? Is it possible to run into deadlock here, e.g.,
user request flush while holding some frames?
> +
> #define OFFSET(x) offsetof(V4L2m2mPriv, x)
> #define FLAGS AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_DECODING_PARAM
>
> @@ -230,6 +282,11 @@ static const AVOption options[] = {
> { NULL},
> };
>
> +static const AVCodecHWConfigInternal *v4l2_m2m_hw_configs[] = {
> + HW_CONFIG_INTERNAL(DRM_PRIME),
Depends on whether allow user to specify drm device.
> + NULL
> +};
> +
> #define M2MDEC_CLASS(NAME) \
> static const AVClass v4l2_m2m_ ## NAME ## _dec_class = { \
> .class_name = #NAME "_v4l2m2m_decoder", \
> @@ -250,7 +307,12 @@ static const AVOption options[] = {
> .init = v4l2_decode_init, \
> FF_CODEC_RECEIVE_FRAME_CB(v4l2_receive_frame), \
> .close = v4l2_decode_close, \
> + .flush = v4l2_flush, \
> + .p.pix_fmts = (const enum AVPixelFormat[]) { AV_PIX_FMT_DRM_PRIME, \
> + AV_PIX_FMT_NV12, \
> + AV_PIX_FMT_NONE}, \
> .bsfs = bsf_name, \
> + .hw_configs = v4l2_m2m_hw_configs, \
> .p.capabilities = AV_CODEC_CAP_HARDWARE | AV_CODEC_CAP_DELAY | AV_CODEC_CAP_AVOID_PROBING, \
> .caps_internal = FF_CODEC_CAP_NOT_INIT_THREADSAFE | \
> FF_CODEC_CAP_INIT_CLEANUP, \
> --
> 2.43.0
>
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