On 2025-02-25 21:42:13, Scott Theisen wrote:
On 2/25/25 13:43, Timo Rothenpieler wrote:
---
libavcodec/cuviddec.c | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)
diff --git a/libavcodec/cuviddec.c b/libavcodec/cuviddec.c
index 67076a1752..312742fb8c 100644
--- a/libavcodec/cuviddec.c
+++ b/libavcodec/cuviddec.c
@@ -131,7 +131,7 @@ static int CUDAAPI
cuvid_handle_video_sequence(void *opaque, CUVIDEOFORMAT* form
CUVIDDECODECREATEINFO cuinfo;
int surface_fmt;
int chroma_444;
- int fifo_size_inc;
+ int old_nb_surfaces, fifo_size_inc, fifo_size_mul = 1;
int old_width = avctx->width;
int old_height = avctx->height;
@@ -349,20 +349,24 @@ static int CUDAAPI
cuvid_handle_video_sequence(void *opaque, CUVIDEOFORMAT* form
return 0;
}
- fifo_size_inc = ctx->nb_surfaces;
- ctx->nb_surfaces = FFMAX(ctx->nb_surfaces,
format->min_num_decode_surfaces + 3);
+ if (ctx->deint_mode_current != cudaVideoDeinterlaceMode_Weave &&
!ctx->drop_second_field) {
+ avctx->framerate = av_mul_q(avctx->framerate,
(AVRational){2, 1});
+ fifo_size_mul = 2;
+ }
+ old_nb_surfaces = ctx->nb_surfaces;
+ ctx->nb_surfaces = FFMAX(ctx->nb_surfaces,
format->min_num_decode_surfaces + 3);
if (avctx->extra_hw_frames > 0)
ctx->nb_surfaces += avctx->extra_hw_frames;
- fifo_size_inc = ctx->nb_surfaces - fifo_size_inc;
+ fifo_size_inc = ctx->nb_surfaces * fifo_size_mul -
av_fifo_can_read(ctx->frame_queue) -
av_fifo_can_write(ctx->frame_queue);
if (fifo_size_inc > 0 && av_fifo_grow2(ctx->frame_queue,
fifo_size_inc) < 0) {
av_log(avctx, AV_LOG_ERROR, "Failed to grow frame queue on
video sequence callback\n");
ctx->internal_error = AVERROR(ENOMEM);
return 0;
}
- if (fifo_size_inc > 0 && av_reallocp_array(&ctx->key_frame,
ctx->nb_surfaces, sizeof(int)) < 0) {
+ if (ctx->nb_surfaces > old_nb_surfaces &&
av_reallocp_array(&ctx->key_frame, ctx->nb_surfaces, sizeof(int)) < 0) {
av_log(avctx, AV_LOG_ERROR, "Failed to grow key frame array
on video sequence callback\n");
ctx->internal_error = AVERROR(ENOMEM);
return 0;
@@ -374,9 +378,6 @@ static int CUDAAPI
cuvid_handle_video_sequence(void *opaque, CUVIDEOFORMAT* form
cuinfo.bitDepthMinus8 = format->bit_depth_luma_minus8;
cuinfo.DeinterlaceMode = ctx->deint_mode_current;
- if (ctx->deint_mode_current != cudaVideoDeinterlaceMode_Weave
&& !ctx->drop_second_field)
- avctx->framerate = av_mul_q(avctx->framerate,
(AVRational){2, 1});
-
ctx->internal_error =
CHECK_CU(ctx->cvdl->cuvidCreateDecoder(&ctx->cudecoder, &cuinfo));
if (ctx->internal_error < 0)
return 0;
@@ -448,11 +449,12 @@ static int cuvid_is_buffer_full(AVCodecContext
*avctx)
{
CuvidContext *ctx = avctx->priv_data;
- int delay = ctx->cuparseinfo.ulMaxDisplayDelay;
+ int mult = 1;
if (ctx->deint_mode != cudaVideoDeinterlaceMode_Weave &&
!ctx->drop_second_field)
- delay *= 2;
+ mult = 2;
- return av_fifo_can_read(ctx->frame_queue) + delay >=
ctx->nb_surfaces;
+ // "- mult + 1" ensures that the buffer is still signalled full
if one half-frame has already been returned when deinterlacing.
+ return av_fifo_can_read(ctx->frame_queue) +
(ctx->cuparseinfo.ulMaxDisplayDelay * mult) >= ctx->nb_surfaces *
mult - mult + 1;
I think this is clearer:
return ((av_fifo_can_read(ctx->frame_queue) + mult - 1) / mult) +
ctx->cuparseinfo.ulMaxDisplayDelay >= ctx->nb_surfaces
Integer ceiling division to get the number of referenced surfaces in
frame_queue.
However, when going from mult = 2 to 1, it thinks the buffer is more
full than it really is, which probably isn't a problem. Unfortunately,
when going from mult = 1 to 2, if there is more than one frame in
frame_queue, it will think there are less surfaces referenced than
there are, which may be a problem.
To avoid that, on transitions you would have to drain frame_queue
until it is empty or peek at what is in frame_queue to actually count
the number of referenced surfaces.
}
static int cuvid_decode_packet(AVCodecContext *avctx, const
AVPacket *avpkt)
I'll apply this to MythTV for testing.
Using this patch instead of my original suggestion also resolves the
playback issue with MythTV.
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