From 3fc72c9fc16df3b7edc329ed9eeaaa1e65976c33 Mon Sep 17 00:00:00 2001 From: Ming Qian Date: Tue, 4 Jan 2022 17:08:32 +0800 Subject: [PATCH] avcodec/v4l2_context: send start decode command after dynamic resolution change event Fixes decoding of sample https://streams.videolan.org/ffmpeg/incoming/720p60.mp4 on RPi4 after kernel driver commit: staging: bcm2835-codec: Format changed should trigger drain Reference: linux/Documentation/userspace-api/media/v4l/dev-decoder.rst "A source change triggers an implicit decoder drain, similar to the explicit Drain sequence. The decoder is stopped after it completes. The decoding process must be resumed with either a pair of calls to VIDIOC_STREAMOFF and VIDIOC_STREAMON on the CAPTURE queue, or a call to VIDIOC_DECODER_CMD with the V4L2_DEC_CMD_START command." Reviewed-by: Andriy Gelman Signed-off-by: Ming Qian --- libavcodec/v4l2_context.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/libavcodec/v4l2_context.c b/libavcodec/v4l2_context.c index dda5157698..a181f884d2 100644 --- a/libavcodec/v4l2_context.c +++ b/libavcodec/v4l2_context.c @@ -153,6 +153,21 @@ static inline void v4l2_save_to_context(V4L2Context* ctx, struct v4l2_format_upd } } +static int v4l2_start_decode(V4L2Context *ctx) +{ + struct v4l2_decoder_cmd cmd = { + .cmd = V4L2_DEC_CMD_START, + .flags = 0, + }; + int ret; + + ret = ioctl(ctx_to_m2mctx(ctx)->fd, VIDIOC_DECODER_CMD, &cmd); + if (ret) + return AVERROR(errno); + + return 0; +} + /** * handle resolution change event and end of stream event * returns 1 if reinit was successful, negative if it failed @@ -190,6 +205,9 @@ static int v4l2_handle_event(V4L2Context *ctx) s->capture.height = v4l2_get_height(&cap_fmt); s->capture.width = v4l2_get_width(&cap_fmt); s->capture.sample_aspect_ratio = v4l2_get_sar(&s->capture); + } else { + v4l2_start_decode(ctx); + return 0; } if (reinit)