[FFmpeg-devel] [PATCH 2/3] lavd/decklink_dec: add support for teletext
Marton Balint
cus at passwd.hu
Thu Jan 14 22:36:21 CET 2016
It uses the libzvbi slicer, therefore teletext capture requires libzvbi.
Signed-off-by: Marton Balint <cus at passwd.hu>
---
doc/indevs.texi | 10 +++++
libavdevice/decklink_common.h | 2 +
libavdevice/decklink_common_c.h | 1 +
libavdevice/decklink_dec.cpp | 99 +++++++++++++++++++++++++++++++++++++++++
libavdevice/decklink_dec_c.c | 3 ++
5 files changed, 115 insertions(+)
diff --git a/doc/indevs.texi b/doc/indevs.texi
index 6cf626d..a3ed0e7 100644
--- a/doc/indevs.texi
+++ b/doc/indevs.texi
@@ -236,6 +236,16 @@ Defaults to @option{false}.
If set to @samp{1}, video is captured in 10 bit v210 instead
of uyvy422. Not all Blackmagic devices support this option.
+ at 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 in 8 bit mode.
+To use this option, ffmpeg needs to be compiled with @code{--enable-libzvbi}.
+
@end table
@subsection Examples
diff --git a/libavdevice/decklink_common.h b/libavdevice/decklink_common.h
index 3bc30f0..076c625 100644
--- a/libavdevice/decklink_common.h
+++ b/libavdevice/decklink_common.h
@@ -67,10 +67,12 @@ struct decklink_ctx {
unsigned int dropped;
AVStream *audio_st;
AVStream *video_st;
+ AVStream *teletext_st;
/* Options */
int list_devices;
int list_formats;
+ int64_t teletext_lines;
double preroll;
int frames_preroll;
diff --git a/libavdevice/decklink_common_c.h b/libavdevice/decklink_common_c.h
index fb2b788..2b1a579 100644
--- a/libavdevice/decklink_common_c.h
+++ b/libavdevice/decklink_common_c.h
@@ -27,6 +27,7 @@ struct decklink_cctx {
/* Options */
int list_devices;
int list_formats;
+ int64_t teletext_lines;
double preroll;
int v210;
};
diff --git a/libavdevice/decklink_dec.cpp b/libavdevice/decklink_dec.cpp
index 89f93de..595d345 100644
--- a/libavdevice/decklink_dec.cpp
+++ b/libavdevice/decklink_dec.cpp
@@ -25,14 +25,47 @@
#include <semaphore.h>
extern "C" {
+#include "config.h"
#include "libavformat/avformat.h"
#include "libavformat/internal.h"
#include "libavutil/imgutils.h"
+#if CONFIG_LIBZVBI
+#include <libzvbi.h>
+#endif
}
#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;
+ if (line >= 7 && line <= 22)
+ ret += line;
+ if (line >= 320 && line <= 335)
+ ret += (line - 313);
+ return ret;
+}
+
+int teletext_data_unit_from_vbi_data(int line, uint8_t *src, uint8_t *tgt)
+{
+ vbi_bit_slicer slicer;
+
+ vbi_bit_slicer_init(&slicer, 720, 13500000, 6937500, 6937500, 0x00aaaae4, 0xffff, 18, 6, 42 * 8, VBI_MODULATION_NRZ_MSB, VBI_PIXFMT_UYVY);
+
+ if (vbi_bit_slice(&slicer, src, tgt + 4) == FALSE)
+ return -1;
+
+ tgt[0] = 0x02; // data_unit_id
+ tgt[1] = 0x2c; // data_unit_length
+ tgt[2] = calc_parity_and_line_offset(line); // field_parity, line_offset
+ tgt[3] = 0xe4; // framing code
+
+ return 0;
+}
+#endif
+
static void avpacket_queue_init(AVFormatContext *avctx, AVPacketQueue *q)
{
memset(q, 0, sizeof(AVPacketQueue));
@@ -277,6 +310,50 @@ HRESULT decklink_input_callback::VideoInputFrameArrived(
pkt.size = videoFrame->GetRowBytes() *
videoFrame->GetHeight();
//fprintf(stderr,"Video Frame size %d ts %d\n", pkt.size, pkt.pts);
+
+#if CONFIG_LIBZVBI
+ if (!no_video && ctx->teletext_lines && videoFrame->GetPixelFormat() == bmdFormat8BitYUV && videoFrame->GetWidth() == 720) {
+ IDeckLinkVideoFrameAncillary *vanc;
+ AVPacket txt_pkt;
+ uint8_t txt_buf0[1611]; // max 35 * 46 bytes decoded teletext lines + 1 byte data_identifier
+ uint8_t *txt_buf = txt_buf0;
+
+ if (videoFrame->GetAncillaryData(&vanc) == S_OK) {
+ int i;
+ int64_t line_mask = 1;
+ txt_buf[0] = 0x10; // data_identifier - EBU_data
+ txt_buf++;
+ for (i = 6; i < 336; i++, line_mask <<= 1) {
+ uint8_t *buf;
+ if ((ctx->teletext_lines & line_mask) && vanc->GetBufferForVerticalBlankingLine(i, (void**)&buf) == S_OK) {
+ if (teletext_data_unit_from_vbi_data(i, buf, txt_buf) >= 0)
+ txt_buf += 46;
+ }
+ if (i == 22)
+ i = 317;
+ }
+ vanc->Release();
+ if (txt_buf - txt_buf0 > 1) {
+ int stuffing_units = (4 - ((45 + txt_buf - txt_buf0) / 46) % 4) % 4;
+ while (stuffing_units--) {
+ memset(txt_buf, 0xff, 46);
+ txt_buf[1] = 0x2c; // data_unit_length
+ txt_buf += 46;
+ }
+ av_init_packet(&txt_pkt);
+ txt_pkt.pts = pkt.pts;
+ txt_pkt.dts = pkt.dts;
+ txt_pkt.stream_index = ctx->teletext_st->index;
+ txt_pkt.data = txt_buf0;
+ txt_pkt.size = txt_buf - txt_buf0;
+ if (avpacket_queue_put(&ctx->queue, &txt_pkt) < 0) {
+ ++ctx->dropped;
+ }
+ }
+ }
+ }
+#endif
+
c->frame_number++;
if (avpacket_queue_put(&ctx->queue, &pkt) < 0) {
++ctx->dropped;
@@ -378,9 +455,17 @@ av_cold int ff_decklink_read_header(AVFormatContext *avctx)
return AVERROR(ENOMEM);
ctx->list_devices = cctx->list_devices;
ctx->list_formats = cctx->list_formats;
+ ctx->teletext_lines = cctx->teletext_lines;
ctx->preroll = cctx->preroll;
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
+
iter = CreateDeckLinkIteratorInstance();
if (!iter) {
av_log(avctx, AV_LOG_ERROR, "Could not create DeckLink iterator\n");
@@ -488,6 +573,20 @@ av_cold int ff_decklink_read_header(AVFormatContext *avctx)
ctx->video_st=st;
+ if (ctx->teletext_lines) {
+ st = avformat_new_stream(avctx, NULL);
+ if (!st) {
+ av_log(avctx, AV_LOG_ERROR, "Cannot add stream\n");
+ goto error;
+ }
+ st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
+ st->codec->time_base.den = ctx->bmd_tb_den;
+ st->codec->time_base.num = ctx->bmd_tb_num;
+ st->codec->codec_id = AV_CODEC_ID_DVB_TELETEXT;
+ avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */
+ ctx->teletext_st = st;
+ }
+
result = ctx->dli->EnableAudioInput(bmdAudioSampleRate48kHz, bmdAudioSampleType16bitInteger, 2);
if (result != S_OK) {
diff --git a/libavdevice/decklink_dec_c.c b/libavdevice/decklink_dec_c.c
index b1a65e6..e5d6bc0 100644
--- a/libavdevice/decklink_dec_c.c
+++ b/libavdevice/decklink_dec_c.c
@@ -32,6 +32,9 @@ static const AVOption options[] = {
{ "list_devices", "list available devices" , OFFSET(list_devices), AV_OPT_TYPE_INT , { .i64 = 0 }, 0, 1, DEC },
{ "list_formats", "list supported formats" , OFFSET(list_formats), AV_OPT_TYPE_INT , { .i64 = 0 }, 0, 1, DEC },
{ "bm_v210", "v210 10 bit per channel" , OFFSET(v210), AV_OPT_TYPE_INT , { .i64 = 0 }, 0, 1, DEC },
+ { "teletext_lines", "teletext lines bitmask", OFFSET(teletext_lines), AV_OPT_TYPE_INT64, { .i64 = 0 }, 0, 0x7ffffffffLL, DEC, "teletext_lines"},
+ { "standard", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = 0x7fff9fffeLL}, 0, 0, DEC, "teletext_lines"},
+ { "all", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = 0x7ffffffffLL}, 0, 0, DEC, "teletext_lines"},
{ NULL },
};
--
2.6.2
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