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avdevice/decklink_dec: Added Closed caption decode from VANC

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Signed-off-by: Karthick J <kjeyapal@akamai.com>
Signed-off-by: Marton Balint <cus@passwd.hu>
This commit is contained in:
Karthick J 2017-08-30 11:43:16 +05:30 committed by Marton Balint
parent a8755785d7
commit b6cf66ae1c
5 changed files with 194 additions and 21 deletions
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3
doc/APIchanges
View File

@ -15,6 +15,9 @@ libavutil: 2015-08-28
API changes, most recent first:
2017-09-28 - xxxxxxx - lavc 57.106.104 - avcodec.h
Add AV_PKT_DATA_A53_CC packet side data, to export closed captions
2017-09-27 - xxxxxxx - lavu 55.77.101 / lavu 55.31.1 - frame.h
Allow passing the value of 0 (meaning "automatic") as the required alignment
to av_frame_get_buffer().

7
libavcodec/avcodec.h
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@ -1599,6 +1599,13 @@ enum AVPacketSideDataType {
*/
AV_PKT_DATA_CONTENT_LIGHT_LEVEL,
/**
* ATSC A53 Part 4 Closed Captions. This metadata should be associated with
* a video stream. A53 CC bitstream is stored as uint8_t in AVPacketSideData.data.
* The number of bytes of CC data is AVPacketSideData.size.
*/
AV_PKT_DATA_A53_CC,
/**
* The number of side data elements (in fact a bit more than it).
* This is not part of the public API/ABI in the sense that it may

1
libavcodec/avpacket.c
View File

@ -387,6 +387,7 @@ const char *av_packet_side_data_name(enum AVPacketSideDataType type)
case AV_PKT_DATA_MASTERING_DISPLAY_METADATA: return "Mastering display metadata";
case AV_PKT_DATA_CONTENT_LIGHT_LEVEL: return "Content light level metadata";
case AV_PKT_DATA_SPHERICAL: return "Spherical Mapping";
case AV_PKT_DATA_A53_CC: return "A53 Closed Captions";
}
return NULL;
}

2
libavcodec/version.h
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@ -29,7 +29,7 @@
#define LIBAVCODEC_VERSION_MAJOR 57
#define LIBAVCODEC_VERSION_MINOR 106
#define LIBAVCODEC_VERSION_MICRO 103
#define LIBAVCODEC_VERSION_MICRO 104
#define LIBAVCODEC_VERSION_INT AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
LIBAVCODEC_VERSION_MINOR, \

202
libavdevice/decklink_dec.cpp
View File

@ -1,6 +1,7 @@
/*
* Blackmagic DeckLink input
* Copyright (c) 2013-2014 Luca Barbato, Deti Fliegl
* Copyright (c) 2014 Rafaël Carré
* Copyright (c) 2017 Akamai Technologies, Inc.
*
* This file is part of FFmpeg.
@ -105,6 +106,42 @@ static int get_vanc_line_idx(BMDDisplayMode mode)
return i - 1;
}
static inline uint16_t parity (uint16_t x)
{
uint16_t i;
for (i = 4 * sizeof (x); i > 0; i /= 2)
x ^= x >> i;
return x & 1;
}
static inline void clear_parity_bits(uint16_t *buf, int len) {
int i;
for (i = 0; i < len; i++)
buf[i] &= 0xff;
}
static int check_vanc_parity_checksum(uint16_t *buf, int len, uint16_t checksum) {
int i;
uint16_t vanc_sum = 0;
for (i = 3; i < len - 1; i++) {
uint16_t v = buf[i];
int np = v >> 8;
int p = parity(v & 0xff);
if ((!!p ^ !!(v & 0x100)) || (np != 1 && np != 2)) {
// Parity check failed
return -1;
}
vanc_sum += v;
}
vanc_sum &= 0x1ff;
vanc_sum |= ((~vanc_sum & 0x100) << 1);
if (checksum != vanc_sum) {
// Checksum verification failed
return -1;
}
return 0;
}
/* The 10-bit VANC data is packed in V210, we only need the luma component. */
static void extract_luma_from_v210(uint16_t *dst, const uint8_t *src, int width)
{
@ -232,19 +269,148 @@ static uint8_t* teletext_data_unit_from_ancillary_packet(uint16_t *py, uint16_t
return tgt;
}
static uint8_t* teletext_data_unit_from_vanc_data(uint16_t *py, uint8_t *tgt, int64_t wanted_lines)
uint8_t *vanc_to_cc(AVFormatContext *avctx, uint16_t *buf, size_t words,
unsigned &cc_count)
{
uint16_t *pend = py + 1920;
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++;
}
size_t i, len = (buf[5] & 0xff) + 6 + 1;
uint8_t cdp_sum, rate;
uint16_t hdr, ftr;
uint8_t *cc;
uint16_t *cdp = &buf[6]; // CDP follows
if (cdp[0] != 0x96 || cdp[1] != 0x69) {
av_log(avctx, AV_LOG_WARNING, "Invalid CDP header 0x%.2x 0x%.2x\n", cdp[0], cdp[1]);
return NULL;
}
len -= 7; // remove VANC header and checksum
if (cdp[2] != len) {
av_log(avctx, AV_LOG_WARNING, "CDP len %d != %zu\n", cdp[2], len);
return NULL;
}
cdp_sum = 0;
for (i = 0; i < len - 1; i++)
cdp_sum += cdp[i];
cdp_sum = cdp_sum ? 256 - cdp_sum : 0;
if (cdp[len - 1] != cdp_sum) {
av_log(avctx, AV_LOG_WARNING, "CDP checksum invalid 0x%.4x != 0x%.4x\n", cdp_sum, cdp[len-1]);
return NULL;
}
rate = cdp[3];
if (!(rate & 0x0f)) {
av_log(avctx, AV_LOG_WARNING, "CDP frame rate invalid (0x%.2x)\n", rate);
return NULL;
}
rate >>= 4;
if (rate > 8) {
av_log(avctx, AV_LOG_WARNING, "CDP frame rate invalid (0x%.2x)\n", rate);
return NULL;
}
if (!(cdp[4] & 0x43)) /* ccdata_present | caption_service_active | reserved */ {
av_log(avctx, AV_LOG_WARNING, "CDP flags invalid (0x%.2x)\n", cdp[4]);
return NULL;
}
hdr = (cdp[5] << 8) | cdp[6];
if (cdp[7] != 0x72) /* ccdata_id */ {
av_log(avctx, AV_LOG_WARNING, "Invalid ccdata_id 0x%.2x\n", cdp[7]);
return NULL;
}
cc_count = cdp[8];
if (!(cc_count & 0xe0)) {
av_log(avctx, AV_LOG_WARNING, "Invalid cc_count 0x%.2x\n", cc_count);
return NULL;
}
cc_count &= 0x1f;
if ((len - 13) < cc_count * 3) {
av_log(avctx, AV_LOG_WARNING, "Invalid cc_count %d (> %zu)\n", cc_count * 3, len - 13);
return NULL;
}
if (cdp[len - 4] != 0x74) /* footer id */ {
av_log(avctx, AV_LOG_WARNING, "Invalid footer id 0x%.2x\n", cdp[len-4]);
return NULL;
}
ftr = (cdp[len - 3] << 8) | cdp[len - 2];
if (ftr != hdr) {
av_log(avctx, AV_LOG_WARNING, "Header 0x%.4x != Footer 0x%.4x\n", hdr, ftr);
return NULL;
}
cc = (uint8_t *)av_malloc(cc_count * 3);
if (cc == NULL) {
av_log(avctx, AV_LOG_WARNING, "CC - av_malloc failed for cc_count = %d\n", cc_count);
return NULL;
}
for (size_t i = 0; i < cc_count; i++) {
cc[3*i + 0] = cdp[9 + 3*i+0] /* & 3 */;
cc[3*i + 1] = cdp[9 + 3*i+1];
cc[3*i + 2] = cdp[9 + 3*i+2];
}
cc_count *= 3;
return cc;
}
uint8_t *get_metadata(AVFormatContext *avctx, uint16_t *buf, size_t width,
uint8_t *tgt, size_t tgt_size, AVPacket *pkt)
{
decklink_cctx *cctx = (struct decklink_cctx *) avctx->priv_data;
uint16_t *max_buf = buf + width;
while (buf < max_buf - 6) {
int len;
uint16_t did = buf[3] & 0xFF; // data id
uint16_t sdid = buf[4] & 0xFF; // secondary data id
/* Check for VANC header */
if (buf[0] != 0 || buf[1] != 0x3ff || buf[2] != 0x3ff) {
return tgt;
}
len = (buf[5] & 0xff) + 6 + 1;
if (len > max_buf - buf) {
av_log(avctx, AV_LOG_WARNING, "Data Count (%d) > data left (%zu)\n",
len, max_buf - buf);
return tgt;
}
if (did == 0x43 && (sdid == 0x02 || sdid == 0x03) && cctx->teletext_lines &&
width == 1920 && tgt_size >= 1920) {
if (check_vanc_parity_checksum(buf, len, buf[len - 1]) < 0) {
av_log(avctx, AV_LOG_WARNING, "VANC parity or checksum incorrect\n");
goto skip_packet;
}
tgt = teletext_data_unit_from_ancillary_packet(buf + 3, buf + len, tgt, cctx->teletext_lines, 0);
} else if (did == 0x61 && sdid == 0x01) {
unsigned int data_len;
uint8_t *data;
if (check_vanc_parity_checksum(buf, len, buf[len - 1]) < 0) {
av_log(avctx, AV_LOG_WARNING, "VANC parity or checksum incorrect\n");
goto skip_packet;
}
clear_parity_bits(buf, len);
data = vanc_to_cc(avctx, buf, width, data_len);
if (data) {
uint8_t *pkt_cc = av_packet_new_side_data(pkt, AV_PKT_DATA_A53_CC, data_len);
if (pkt_cc)
memcpy(pkt_cc, data, data_len);
av_free(data);
}
} else {
av_log(avctx, AV_LOG_DEBUG, "Unknown meta data DID = 0x%.2x SDID = 0x%.2x\n",
did, sdid);
}
skip_packet:
buf += len;
}
return tgt;
}
@ -536,7 +702,7 @@ HRESULT decklink_input_callback::VideoInputFrameArrived(
videoFrame->GetHeight();
//fprintf(stderr,"Video Frame size %d ts %d\n", pkt.size, pkt.pts);
if (!no_video && ctx->teletext_lines) {
if (!no_video) {
IDeckLinkVideoFrameAncillary *vanc;
AVPacket txt_pkt;
uint8_t txt_buf0[3531]; // 35 * 46 bytes decoded teletext lines + 1 byte data_identifier + 1920 bytes OP47 decode buffer
@ -549,7 +715,8 @@ HRESULT decklink_input_callback::VideoInputFrameArrived(
txt_buf[0] = 0x10; // data_identifier - EBU_data
txt_buf++;
#if CONFIG_LIBZVBI
if (ctx->bmd_mode == bmdModePAL && (vanc_format == bmdFormat8BitYUV || vanc_format == bmdFormat10BitYUV)) {
if (ctx->bmd_mode == bmdModePAL && ctx->teletext_lines &&
(vanc_format == bmdFormat8BitYUV || vanc_format == bmdFormat10BitYUV)) {
av_assert0(videoFrame->GetWidth() == 720);
for (i = 6; i < 336; i++, line_mask <<= 1) {
uint8_t *buf;
@ -571,13 +738,8 @@ HRESULT decklink_input_callback::VideoInputFrameArrived(
if (vanc->GetBufferForVerticalBlankingLine(i, (void**)&buf) == S_OK) {
uint16_t luma_vanc[MAX_WIDTH_VANC];
extract_luma_from_v210(luma_vanc, buf, videoFrame->GetWidth());
if (videoFrame->GetWidth() == 1920) {
txt_buf = teletext_data_unit_from_vanc_data(luma_vanc, txt_buf, ctx->teletext_lines);
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;
}
}
txt_buf = get_metadata(avctx, luma_vanc, videoFrame->GetWidth(),
txt_buf, sizeof(txt_buf0) - (txt_buf - txt_buf0), &pkt);
}
if (i == vanc_line_numbers[idx].field0_vanc_end)
i = vanc_line_numbers[idx].field1_vanc_start - 1;