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FFmpeg: Update v4l2 memory to memory DRM_PRIME support
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- this brings our v4l2 patches in line with patches 15 and 16 from Aman
Gupta's last patch set submitted to FFmpeg (https://ffmpeg.org/
pipermail/ffmpeg-devel/2019-September/thread.html#249359)
- adds ifdeffery to fix build when libdrm is not available
- uses correct V4L2 memory type for output and capture contexts (athough
this doesn't seem to make any noticeable difference on the Pi 4 when
tested)
- pix format negotiation is largely shifted to v4l2_context - sw_pix_fmt
should now be set properly (allowing simplification of MythEGLDMABUG
code)
- NOTE: there was an issue with the v4l2_buffers.c code that broke
playback - the switch in v4l2_get_drm_frame has been amened to reference
sw_pix_fmt (av_pix_fmt is always AV_PIX_FMT_PRIME)
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@mark-kendall
mark-kendall committed Jul 26, 2020
1 parent d0f923b commit a1e378a
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Showing 6 changed files with 183 additions and 136 deletions.
183 changes: 93 additions & 90 deletions mythtv/external/FFmpeg/libavcodec/v4l2_buffers.c
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Original file line number Diff line number Diff line change
Expand Up @@ -21,7 +21,11 @@
* 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>
Expand All @@ -30,8 +34,9 @@
#include <poll.h>
#include "libavcodec/avcodec.h"
#include "libavcodec/internal.h"
#include "libavutil/pixdesc.h"
#include "libavutil/avassert.h"
#include "libavutil/hwcontext.h"
#include "libavutil/pixdesc.h"
#include "v4l2_context.h"
#include "v4l2_buffers.h"
#include "v4l2_m2m.h"
Expand Down Expand Up @@ -231,7 +236,52 @@ static enum AVColorTransferCharacteristic v4l2_get_color_trc(V4L2Buffer *buf)
return AVCOL_TRC_UNSPECIFIED;
}

static uint8_t * v4l2_get_drm_frame(V4L2Buffer *avbuf)
static void v4l2_free_buffer(void *opaque, uint8_t *unused)
{
V4L2Buffer* avbuf = opaque;
V4L2m2mContext *s = buf_to_m2mctx(avbuf);

if (atomic_fetch_sub(&avbuf->context_refcount, 1) == 1) {
atomic_fetch_sub_explicit(&s->refcount, 1, memory_order_acq_rel);

if (s->reinit) {
if (!atomic_load(&s->refcount))
sem_post(&s->refsync);
} else {
if (s->draining && V4L2_TYPE_IS_OUTPUT(avbuf->context->type)) {
/* no need to queue more buffers to the driver */
avbuf->status = V4L2BUF_AVAILABLE;
}
else if (avbuf->context->streamon)
ff_v4l2_buffer_enqueue(avbuf);
}

av_buffer_unref(&avbuf->context_ref);
}
}

static int v4l2_buf_increase_ref(V4L2Buffer *in)
{
V4L2m2mContext *s = buf_to_m2mctx(in);

if (in->context_ref)
atomic_fetch_add(&in->context_refcount, 1);
else {
in->context_ref = av_buffer_ref(s->self_ref);
if (!in->context_ref)
return AVERROR(ENOMEM);

in->context_refcount = 1;
}

in->status = V4L2BUF_RET_USER;
atomic_fetch_add_explicit(&s->refcount, 1, memory_order_relaxed);

return 0;
}

#if CONFIG_LIBDRM
static uint8_t *v4l2_get_drm_frame(V4L2Buffer *avbuf)
{
AVDRMFrameDescriptor *drm_desc = &avbuf->drm_frame;
AVDRMLayerDescriptor *layer;
Expand All @@ -249,17 +299,15 @@ static uint8_t * v4l2_get_drm_frame(V4L2Buffer *avbuf)
layer->planes[i].pitch = avbuf->plane_info[i].bytesperline;
}

switch (avbuf->context->av_pix_fmt) {
switch (avbuf->context->sw_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;

Expand All @@ -275,7 +323,6 @@ static uint8_t * v4l2_get_drm_frame(V4L2Buffer *avbuf)
break;

case AV_PIX_FMT_YUV420P:

layer->format = DRM_FORMAT_YUV420;

if (avbuf->num_planes > 1)
Expand All @@ -300,31 +347,7 @@ static uint8_t * v4l2_get_drm_frame(V4L2Buffer *avbuf)
break;
}

return (uint8_t *) drm_desc;
}

static void v4l2_free_buffer(void *opaque, uint8_t *data)
{
V4L2Buffer* avbuf = opaque;
V4L2m2mContext *s = buf_to_m2mctx(avbuf);

if (atomic_fetch_sub(&avbuf->context_refcount, 1) == 1) {
atomic_fetch_sub_explicit(&s->refcount, 1, memory_order_acq_rel);

if (s->reinit) {
if (!atomic_load(&s->refcount))
sem_post(&s->refsync);
} else {
if (s->draining && V4L2_TYPE_IS_OUTPUT(avbuf->context->type)) {
/* no need to queue more buffers to the driver */
avbuf->status = V4L2BUF_AVAILABLE;
}
else if (avbuf->context->streamon)
ff_v4l2_buffer_enqueue(avbuf);
}

av_buffer_unref(&avbuf->context_ref);
}
return (uint8_t *)drm_desc;
}

static int v4l2_buffer_export_drm(V4L2Buffer* avbuf)
Expand Down Expand Up @@ -359,26 +382,6 @@ static int v4l2_buffer_export_drm(V4L2Buffer* avbuf)
return 0;
}

static int v4l2_buf_increase_ref(V4L2Buffer *in)
{
V4L2m2mContext *s = buf_to_m2mctx(in);

if (in->context_ref)
atomic_fetch_add(&in->context_refcount, 1);
else {
in->context_ref = av_buffer_ref(s->self_ref);
if (!in->context_ref)
return AVERROR(ENOMEM);

in->context_refcount = 1;
}

in->status = V4L2BUF_RET_USER;
atomic_fetch_add_explicit(&s->refcount, 1, memory_order_relaxed);

return 0;
}

static int v4l2_buf_to_bufref_drm(V4L2Buffer *in, AVBufferRef **buf)
{
int ret;
Expand All @@ -396,6 +399,7 @@ static int v4l2_buf_to_bufref_drm(V4L2Buffer *in, AVBufferRef **buf)

return ret;
}
#endif

static int v4l2_buf_to_bufref(V4L2Buffer *in, int plane, AVBufferRef **buf)
{
Expand All @@ -404,7 +408,7 @@ static int v4l2_buf_to_bufref(V4L2Buffer *in, int plane, AVBufferRef **buf)
if (plane >= in->num_planes)
return AVERROR(EINVAL);

/* even though most encoders return 0 in data_offset encoding vp8 does require this value */
/* most encoders return 0 in data_offset but vp8 does require this value */
*buf = av_buffer_create((char *)in->plane_info[plane].mm_addr + in->planes[plane].data_offset,
in->plane_info[plane].length, v4l2_free_buffer, in, 0);
if (!*buf)
Expand Down Expand Up @@ -556,6 +560,21 @@ int ff_v4l2_buffer_avframe_to_buf(const AVFrame *frame, V4L2Buffer *out)
{
v4l2_set_pts(out, frame->pts);

if (frame->format == AV_PIX_FMT_DRM_PRIME) {
AVDRMFrameDescriptor *drm_desc = (AVDRMFrameDescriptor *)frame->data[0];
int i;
av_assert0(out->buf.memory == V4L2_MEMORY_DMABUF);

if (V4L2_TYPE_IS_MULTIPLANAR(out->buf.type)) {
for (i = 0; i < drm_desc->nb_objects; i++) {
out->buf.m.planes[i].m.fd = drm_desc->objects[i].fd;
}
} else {
out->buf.m.fd = drm_desc->objects[0].fd;
}
return 0;
}

return v4l2_buffer_swframe_to_buf(frame, out);
}

Expand All @@ -566,15 +585,16 @@ int ff_v4l2_buffer_buf_to_avframe(AVFrame *frame, V4L2Buffer *avbuf)
av_frame_unref(frame);

/* 1. get references to the actual data */
if (buf_to_m2mctx(avbuf)->output_drm) {
/* 1. get references to the actual data */
if (avbuf->context->av_pix_fmt == AV_PIX_FMT_DRM_PRIME) {
#if CONFIG_LIBDRM
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->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)
Expand Down Expand Up @@ -651,31 +671,11 @@ int ff_v4l2_buffer_initialize(V4L2Buffer* avbuf, int index)
V4L2Context *ctx = avbuf->context;
int ret, i;

avbuf->buf.memory = V4L2_MEMORY_MMAP;
avbuf->buf.memory = ctx->av_pix_fmt == AV_PIX_FMT_DRM_PRIME && V4L2_TYPE_IS_OUTPUT(ctx->type) ?
V4L2_MEMORY_DMABUF : V4L2_MEMORY_MMAP;
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;
Expand Down Expand Up @@ -704,21 +704,21 @@ 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;

if ((V4L2_TYPE_IS_OUTPUT(ctx->type) && buf_to_m2mctx(avbuf)->output_drm) ||
!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);
}
if (ctx->av_pix_fmt == AV_PIX_FMT_DRM_PRIME)
continue;

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;

if ((V4L2_TYPE_IS_OUTPUT(ctx->type) && buf_to_m2mctx(avbuf)->output_drm) ||
!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 (ctx->av_pix_fmt == AV_PIX_FMT_DRM_PRIME)
continue;

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)
Expand All @@ -730,6 +730,7 @@ int ff_v4l2_buffer_initialize(V4L2Buffer* avbuf, int index)
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;
Expand All @@ -738,10 +739,12 @@ int ff_v4l2_buffer_initialize(V4L2Buffer* avbuf, int index)
if (V4L2_TYPE_IS_OUTPUT(ctx->type))
return 0;

if (buf_to_m2mctx(avbuf)->output_drm) {
if (ctx->av_pix_fmt == AV_PIX_FMT_DRM_PRIME) {
#if CONFIG_LIBDRM
ret = v4l2_buffer_export_drm(avbuf);
if (ret)
return ret;
#endif
}

return ff_v4l2_buffer_enqueue(avbuf);
Expand Down
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