[FFmpeg-devel] [PATCHv2 2/2] avdevice/decklink_dec: add support for receiving op47 teletext
Marton Balint
cus at passwd.hu
Sat Jul 8 02:24:24 EEST 2017
v2:
- use uint16_t instead of int to store 10-bit ancillary data
- fix ancillary line numbers for 1080p
- some comments and clarifications as requested by Aaron Levinson
Signed-off-by: Marton Balint <cus at passwd.hu>
---
doc/indevs.texi | 20 ++++---
libavdevice/decklink_dec.cpp | 127 +++++++++++++++++++++++++++++++++++++++----
2 files changed, 129 insertions(+), 18 deletions(-)
diff --git a/doc/indevs.texi b/doc/indevs.texi
index 330617a7c9..09e33216dc 100644
--- a/doc/indevs.texi
+++ b/doc/indevs.texi
@@ -245,13 +245,19 @@ of uyvy422. Not all Blackmagic devices support this option.
@item teletext_lines
If set to nonzero, an additional teletext stream will be captured from the
-vertical ancillary data. This option is a bitmask of the VBI lines checked,
-specifically lines 6 to 22, and lines 318 to 335. Line 6 is the LSB in the mask.
-Selected lines which do not contain teletext information will be ignored. You
-can use the special @option{all} constant to select all possible lines, or
- at option{standard} to skip lines 6, 318 and 319, which are not compatible with all
-receivers. Capturing teletext only works for SD PAL sources. To use this
-option, ffmpeg needs to be compiled with @code{--enable-libzvbi}.
+vertical ancillary data. Both SD PAL (576i) and HD (1080i or 1080p)
+sources are supported. In case of HD sources, OP47 packets are decoded.
+
+This option is a bitmask of the SD PAL VBI lines captured, specifically lines 6
+to 22, and lines 318 to 335. Line 6 is the LSB in the mask. Selected lines
+which do not contain teletext information will be ignored. You can use the
+special @option{all} constant to select all possible lines, or
+ at option{standard} to skip lines 6, 318 and 319, which are not compatible with
+all receivers.
+
+For SD sources, ffmpeg needs to be compiled with @code{--enable-libzvbi}. For
+HD sources, on older (pre-4K) DeckLink card models you have to capture in 10
+bit mode.
@item channels
Defines number of audio channels to capture. Must be @samp{2}, @samp{8} or @samp{16}.
diff --git a/libavdevice/decklink_dec.cpp b/libavdevice/decklink_dec.cpp
index 6783a0ce77..8b5c1a20c1 100644
--- a/libavdevice/decklink_dec.cpp
+++ b/libavdevice/decklink_dec.cpp
@@ -36,6 +36,7 @@ extern "C" {
#include "libavutil/imgutils.h"
#include "libavutil/time.h"
#include "libavutil/mathematics.h"
+#include "libavutil/reverse.h"
#if CONFIG_LIBZVBI
#include <libzvbi.h>
#endif
@@ -44,7 +45,6 @@ extern "C" {
#include "decklink_common.h"
#include "decklink_dec.h"
-#if CONFIG_LIBZVBI
static uint8_t calc_parity_and_line_offset(int line)
{
uint8_t ret = (line < 313) << 5;
@@ -63,6 +63,7 @@ static void fill_data_unit_head(int line, uint8_t *tgt)
tgt[3] = 0xe4; // framing code
}
+#if CONFIG_LIBZVBI
static uint8_t* teletext_data_unit_from_vbi_data(int line, uint8_t *src, uint8_t *tgt, vbi_pixfmt fmt)
{
vbi_bit_slicer slicer;
@@ -95,6 +96,95 @@ static uint8_t* teletext_data_unit_from_vbi_data_10bit(int line, uint8_t *src, u
}
#endif
+static uint8_t* teletext_data_unit_from_op47_vbi_packet(int line, uint16_t *py, uint8_t *tgt)
+{
+ int i;
+
+ if (py[0] != 0x255 || py[1] != 0x255 || py[2] != 0x227)
+ return tgt;
+
+ fill_data_unit_head(line, tgt);
+
+ py += 3;
+ tgt += 4;
+
+ for (i = 0; i < 42; i++)
+ *tgt++ = ff_reverse[py[i] & 255];
+
+ return tgt;
+}
+
+static int linemask_matches(int line, int64_t mask)
+{
+ int shift = -1;
+ if (line >= 6 && line <= 22)
+ shift = line - 6;
+ if (line >= 318 && line <= 335)
+ shift = line - 318 + 17;
+ return shift >= 0 && ((1ULL << shift) & mask);
+}
+
+static uint8_t* teletext_data_unit_from_op47_data(uint16_t *py, uint16_t *pend, uint8_t *tgt, int64_t wanted_lines)
+{
+ if (py < pend - 9) {
+ if (py[0] == 0x151 && py[1] == 0x115 && py[3] == 0x102) { // identifier, identifier, format code for WST teletext
+ uint16_t *descriptors = py + 4;
+ int i;
+ py += 9;
+ for (i = 0; i < 5 && py < pend - 45; i++, py += 45) {
+ int line = (descriptors[i] & 31) + (!(descriptors[i] & 128)) * 313;
+ if (line && linemask_matches(line, wanted_lines))
+ tgt = teletext_data_unit_from_op47_vbi_packet(line, py, tgt);
+ }
+ }
+ }
+ return tgt;
+}
+
+static uint8_t* teletext_data_unit_from_ancillary_packet(uint16_t *py, uint16_t *pend, uint8_t *tgt, int64_t wanted_lines, int allow_multipacket)
+{
+ uint16_t did = py[0]; // data id
+ uint16_t sdid = py[1]; // secondary data id
+ uint16_t dc = py[2] & 255; // data count
+ py += 3;
+ pend = FFMIN(pend, py + dc);
+ if (did == 0x143 && sdid == 0x102) { // subtitle distribution packet
+ tgt = teletext_data_unit_from_op47_data(py, pend, tgt, wanted_lines);
+ } else if (allow_multipacket && did == 0x143 && sdid == 0x203) { // VANC multipacket
+ py += 2; // priority, line/field
+ while (py < pend - 3) {
+ tgt = teletext_data_unit_from_ancillary_packet(py, pend, tgt, wanted_lines, 0);
+ py += 4 + (py[2] & 255); // ndid, nsdid, ndc, line/field
+ }
+ }
+ return tgt;
+}
+
+static uint8_t* teletext_data_unit_from_vanc_data(uint8_t *src, uint8_t *tgt, int64_t wanted_lines)
+{
+ uint16_t y[1920];
+ uint16_t *py = y;
+ uint16_t *pend = y + 1920;
+ /* The 10-bit VANC data is packed in V210, we only need the luma component. */
+ while (py < pend) {
+ *py++ = (src[1] >> 2) + ((src[2] & 15) << 6);
+ *py++ = src[4] + ((src[5] & 3) << 8);
+ *py++ = (src[6] >> 4) + ((src[7] & 63) << 4);
+ src += 8;
+ }
+ py = y;
+ while (py < pend - 6) {
+ if (py[0] == 0 && py[1] == 0x3ff && py[2] == 0x3ff) { // ancillary data flag
+ py += 3;
+ tgt = teletext_data_unit_from_ancillary_packet(py, pend, tgt, wanted_lines, 0);
+ py += py[2] & 255;
+ } else {
+ py++;
+ }
+ }
+ return tgt;
+}
+
static void avpacket_queue_init(AVFormatContext *avctx, AVPacketQueue *q)
{
memset(q, 0, sizeof(AVPacketQueue));
@@ -381,11 +471,10 @@ HRESULT decklink_input_callback::VideoInputFrameArrived(
videoFrame->GetHeight();
//fprintf(stderr,"Video Frame size %d ts %d\n", pkt.size, pkt.pts);
-#if CONFIG_LIBZVBI
if (!no_video && ctx->teletext_lines) {
IDeckLinkVideoFrameAncillary *vanc;
AVPacket txt_pkt;
- uint8_t txt_buf0[1611]; // max 35 * 46 bytes decoded teletext lines + 1 byte data_identifier
+ uint8_t txt_buf0[3531]; // 35 * 46 bytes decoded teletext lines + 1 byte data_identifier + 1920 bytes OP47 decode buffer
uint8_t *txt_buf = txt_buf0;
if (videoFrame->GetAncillaryData(&vanc) == S_OK) {
@@ -394,6 +483,7 @@ HRESULT decklink_input_callback::VideoInputFrameArrived(
BMDPixelFormat vanc_format = vanc->GetPixelFormat();
txt_buf[0] = 0x10; // data_identifier - EBU_data
txt_buf++;
+#if CONFIG_LIBZVBI
if (ctx->bmd_mode == bmdModePAL && (vanc_format == bmdFormat8BitYUV || vanc_format == bmdFormat10BitYUV)) {
av_assert0(videoFrame->GetWidth() == 720);
for (i = 6; i < 336; i++, line_mask <<= 1) {
@@ -408,6 +498,21 @@ HRESULT decklink_input_callback::VideoInputFrameArrived(
i = 317;
}
}
+#endif
+ if (videoFrame->GetWidth() == 1920 && vanc_format == bmdFormat10BitYUV) {
+ int first_active_line = ctx->bmd_field_dominance == bmdProgressiveFrame ? 42 : 584;
+ for (i = 8; i < first_active_line; i++) {
+ uint8_t *buf;
+ if (vanc->GetBufferForVerticalBlankingLine(i, (void**)&buf) == S_OK)
+ txt_buf = teletext_data_unit_from_vanc_data(buf, txt_buf, ctx->teletext_lines);
+ if (ctx->bmd_field_dominance != bmdProgressiveFrame && i == 20) // skip field1 active lines
+ i = 569;
+ if (txt_buf - txt_buf0 > 1611) { // ensure we still have at least 1920 bytes free in the buffer
+ av_log(avctx, AV_LOG_ERROR, "Too many OP47 teletext packets.\n");
+ break;
+ }
+ }
+ }
vanc->Release();
if (txt_buf - txt_buf0 > 1) {
int stuffing_units = (4 - ((45 + txt_buf - txt_buf0) / 46) % 4) % 4;
@@ -428,7 +533,6 @@ HRESULT decklink_input_callback::VideoInputFrameArrived(
}
}
}
-#endif
if (avpacket_queue_put(&ctx->queue, &pkt) < 0) {
++ctx->dropped;
@@ -527,13 +631,6 @@ av_cold int ff_decklink_read_header(AVFormatContext *avctx)
ctx->draw_bars = cctx->draw_bars;
cctx->ctx = ctx;
-#if !CONFIG_LIBZVBI
- if (ctx->teletext_lines) {
- av_log(avctx, AV_LOG_ERROR, "Libzvbi support is needed for capturing teletext, please recompile FFmpeg.\n");
- return AVERROR(ENOSYS);
- }
-#endif
-
/* Check audio channel option for valid values: 2, 8 or 16 */
switch (cctx->audio_channels) {
case 2:
@@ -587,6 +684,14 @@ av_cold int ff_decklink_read_header(AVFormatContext *avctx)
}
}
+#if !CONFIG_LIBZVBI
+ if (ctx->teletext_lines && ctx->bmd_mode == bmdModePAL) {
+ av_log(avctx, AV_LOG_ERROR, "Libzvbi support is needed for capturing SD PAL teletext, please recompile FFmpeg.\n");
+ ret = AVERROR(ENOSYS);
+ goto error;
+ }
+#endif
+
/* Setup streams. */
st = avformat_new_stream(avctx, NULL);
if (!st) {
--
2.12.3
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