diff mbox series

[FFmpeg-devel,v5,3/7] avcodec/v4l2_context: add v4l2_start_decode

Message ID 20220104090836.31660-3-ming.qian@nxp.com
State Accepted
Commit 3fc72c9fc16df3b7edc329ed9eeaaa1e65976c33
Headers show
Series [FFmpeg-devel,v5,1/7] avcodec/v4l2_context: don't reinit output queue when dynamic resolution change | expand

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Commit Message

Ming Qian Jan. 4, 2022, 9:08 a.m. UTC
on dynamic resolution change,
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.

Signed-off-by: Ming Qian <ming.qian@nxp.com>
---
 libavcodec/v4l2_context.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

Comments

Andriy Gelman Jan. 4, 2022, 10:37 p.m. UTC | #1
On Tue, 04. Jan 17:08, Ming Qian wrote:
> on dynamic resolution change,
> 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.
> 

For the patch title, I think something like the following would be better:
avcodec/v4l2_context: send start decode command after dynamic resolution change
event

I'll add that this fixes decoding of 
https://streams.videolan.org/ffmpeg/incoming/720p60.mp4 on RPi4.

> Signed-off-by: Ming Qian <ming.qian@nxp.com>
> ---
>  libavcodec/v4l2_context.c | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
> 
> diff --git a/libavcodec/v4l2_context.c b/libavcodec/v4l2_context.c
> index dda5157698c3..a181f884d2a6 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)

lgtm otherwise.

Thanks
diff mbox series

Patch

diff --git a/libavcodec/v4l2_context.c b/libavcodec/v4l2_context.c
index dda5157698c3..a181f884d2a6 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)