[FFmpeg-devel] [PATCH v3] libavcodec/v4l2_buffers.c: set AVFrame interlaced flags

[Scott Theisen]

Originally from:
https://github.com/MythTV/mythtv/commit/669955c6cb29196b4b5120451b5b998d67a65749

---

v3:
remove unnecessary clearing of already 0 valued flags
use switch-case; I don't really think it is any simpler, but I do like the format better.
---
 libavcodec/v4l2_buffers.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/libavcodec/v4l2_buffers.c b/libavcodec/v4l2_buffers.c
index 23474ee143..19cc86334b 100644
--- a/libavcodec/v4l2_buffers.c
+++ b/libavcodec/v4l2_buffers.c
@@ -210,6 +210,24 @@ static enum AVColorTransferCharacteristic v4l2_get_color_trc(V4L2Buffer *buf)
     return AVCOL_TRC_UNSPECIFIED;
 }
 
+static void v4l2_get_interlacing(AVFrame *frame, V4L2Buffer *buf)
+{
+    enum v4l2_field field;
+    field = V4L2_TYPE_IS_MULTIPLANAR(buf->buf.type) ?
+        buf->context->format.fmt.pix_mp.field :
+        buf->context->format.fmt.pix.field;
+
+    switch (field) {
+    case V4L2_FIELD_INTERLACED:
+    case V4L2_FIELD_INTERLACED_TB:
+        frame->flags |=  AV_FRAME_FLAG_TOP_FIELD_FIRST;
+        /* fallthrough */
+    case V4L2_FIELD_INTERLACED_BT:
+        frame->flags |=  AV_FRAME_FLAG_INTERLACED;
+        break;
+    }
+}
+
 static void v4l2_free_buffer(void *opaque, uint8_t *unused)
 {
     V4L2Buffer* avbuf = opaque;
@@ -434,6 +452,7 @@ int ff_v4l2_buffer_buf_to_avframe(AVFrame *frame, V4L2Buffer *avbuf)
     frame->color_trc = v4l2_get_color_trc(avbuf);
     frame->pts = v4l2_get_pts(avbuf);
     frame->pkt_dts = AV_NOPTS_VALUE;
+    v4l2_get_interlacing(frame, avbuf);
 
     /* these values are updated also during re-init in v4l2_process_driver_event */
     frame->height = avbuf->context->height;
-- 
2.43.0