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[FFmpeg-devel] avdevice/decklink_dec: Extract NTSC VANC

Message ID 1518394605-62027-1-git-send-email-raytiley@gmail.com
State Accepted
Commit c837cd3d4d11b7d304ff83a448831c81a53c8c25
Headers show

Commit Message

Ray Tiley Feb. 12, 2018, 12:16 a.m. UTC 
This changes how NTSC VANC is extracted from the buffer. In NTSC the vanc
data interleved between the uyvy and not just the luma as in
high definition resolutions.

In my testing this allows a decklink card encoding valid NTSC closed
captions to pass the caption data to the x264 encoder.

Updated with rewviews from Devon Heitmueller and Marton Balint.

Signed-off-by: Ray Tiley <raytiley@gmail.com>
---
 libavdevice/decklink_dec.cpp | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

Comments

Marton Balint Feb. 12, 2018, 11:34 p.m. UTC | #1 
On Sun, 11 Feb 2018, Ray Tiley wrote:

> This changes how NTSC VANC is extracted from the buffer. In NTSC the vanc
> data interleved between the uyvy and not just the luma as in
> high definition resolutions.
>
> In my testing this allows a decklink card encoding valid NTSC closed
> captions to pass the caption data to the x264 encoder.
>
> Updated with rewviews from Devon Heitmueller and Marton Balint.
>
> Signed-off-by: Ray Tiley <raytiley@gmail.com>
> ---
> libavdevice/decklink_dec.cpp | 23 ++++++++++++++++++++---
> 1 file changed, 20 insertions(+), 3 deletions(-)

Thanks, applied.

Regards,
Marton
diff mbox

Patch

diff --git a/libavdevice/decklink_dec.cpp b/libavdevice/decklink_dec.cpp
index 5c116f2..c3bb46e 100644
--- a/libavdevice/decklink_dec.cpp
+++ b/libavdevice/decklink_dec.cpp
@@ -149,6 +149,17 @@  static void extract_luma_from_v210(uint16_t *dst, const uint8_t *src, int width)
     }
 }
 
+static void unpack_v210(uint16_t *dst, const uint8_t *src, int width)
+{
+    int i;
+    for (i = 0; i < width * 2 / 3; i++) {
+        *dst++ =  src[0]       + ((src[1] & 3)  << 8);
+        *dst++ = (src[1] >> 2) + ((src[2] & 15) << 6);
+        *dst++ = (src[2] >> 4) + ((src[3] & 63) << 4);
+        src += 4;
+    }
+}
+
 static uint8_t calc_parity_and_line_offset(int line)
 {
     uint8_t ret = (line < 313) << 5;
@@ -752,9 +763,15 @@  HRESULT decklink_input_callback::VideoInputFrameArrived(
                     for (i = vanc_line_numbers[idx].vanc_start; i <= vanc_line_numbers[idx].vanc_end; i++) {
                         uint8_t *buf;
                         if (vanc->GetBufferForVerticalBlankingLine(i, (void**)&buf) == S_OK) {
-                            uint16_t luma_vanc[MAX_WIDTH_VANC];
-                            extract_luma_from_v210(luma_vanc, buf, videoFrame->GetWidth());
-                            txt_buf = get_metadata(avctx, luma_vanc, videoFrame->GetWidth(),
+                            uint16_t vanc[MAX_WIDTH_VANC];
+                            size_t vanc_size = videoFrame->GetWidth();
+                            if (ctx->bmd_mode == bmdModeNTSC && videoFrame->GetWidth() * 2 <= MAX_WIDTH_VANC) {
+                                vanc_size = vanc_size * 2;
+                                unpack_v210(vanc, buf, videoFrame->GetWidth());
+                            } else {
+                                extract_luma_from_v210(vanc, buf, videoFrame->GetWidth());
+                            }
+                            txt_buf = get_metadata(avctx, vanc, vanc_size,
                                                    txt_buf, sizeof(txt_buf0) - (txt_buf - txt_buf0), &pkt);
                         }
                         if (i == vanc_line_numbers[idx].field0_vanc_end)