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Refs #9829. Handle duplicate SCTE and ATSC captions with patch from A…
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…lex Halovanic.

The primary problem is that some streams have both SCTE and ATSC captions, so we need to capture them seperately and then decide which to use.

A secondary problem is inversion and repeats in 608 captions, esp SCTE.
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@daniel-kristjansson
daniel-kristjansson committed Aug 11, 2011
1 parent d986a92 commit d526385
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Showing 7 changed files with 84 additions and 21 deletions.
7 changes: 7 additions & 0 deletions mythtv/external/FFmpeg/libavcodec/avcodec.h
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Expand Up @@ -1060,6 +1060,13 @@ typedef struct AVPanScan{
uint8_t atsc_cc_buf[1024];\
int atsc_cc_len;\
\
/** SCTE CC data CEA-608 \
* - encoding: unused\
* - decoding: Set by libavcodec
*/\
uint8_t scte_cc_buf[1024];\
int scte_cc_len;\
\

#define FF_QSCALE_TYPE_MPEG1 0
#define FF_QSCALE_TYPE_MPEG2 1
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20 changes: 10 additions & 10 deletions mythtv/external/FFmpeg/libavcodec/mpeg12.c
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Expand Up @@ -2168,14 +2168,14 @@ static void mpeg_decode_user_data(AVCodecContext *avctx,
unsigned int cc_bytes = (cc_bits + 7 - 3) / 8;
Mpeg1Context *s1 = avctx->priv_data;
MpegEncContext *s = &s1->mpeg_enc_ctx;
if (buf_end - p >= (2+cc_bytes) && (s->tmp_atsc_cc_len + 2 + 3*cc_count) < ATSC_CC_BUF_SIZE) {
int atsc_cnt_loc = s->tmp_atsc_cc_len;
if (buf_end - p >= (2+cc_bytes) && (s->tmp_scte_cc_len + 2 + 3*cc_count) < SCTE_CC_BUF_SIZE) {
int scte_cnt_loc = s->tmp_scte_cc_len;
uint8_t real_count = 0, marker = 1, i;
GetBitContext gb;
init_get_bits(&gb, p+2, (buf_end-p-2) * sizeof(uint8_t));
get_bits(&gb, 5); // swallow cc_count
s->tmp_atsc_cc_buf[s->tmp_atsc_cc_len++] = 0x40 | (0x1f&cc_count);
s->tmp_atsc_cc_buf[s->tmp_atsc_cc_len++] = 0x00; // em_data
s->tmp_scte_cc_buf[s->tmp_scte_cc_len++] = 0x40 | (0x1f&cc_count);
s->tmp_scte_cc_buf[s->tmp_scte_cc_len++] = 0x00; // em_data
for (i = 0; i < cc_count; i++) {
uint8_t valid, cc608_hdr;
uint8_t priority = get_bits(&gb, 2);
Expand All @@ -2196,18 +2196,18 @@ static void mpeg_decode_user_data(AVCodecContext *avctx,
continue;
cc608_hdr = 0xf8 | (valid ? 0x04 : 0x00) | type;
real_count++;
s->tmp_atsc_cc_buf[s->tmp_atsc_cc_len++] = cc608_hdr;
s->tmp_atsc_cc_buf[s->tmp_atsc_cc_len++] = cc_data_1;
s->tmp_atsc_cc_buf[s->tmp_atsc_cc_len++] = cc_data_2;
s->tmp_scte_cc_buf[s->tmp_scte_cc_len++] = cc608_hdr;
s->tmp_scte_cc_buf[s->tmp_scte_cc_len++] = cc_data_1;
s->tmp_scte_cc_buf[s->tmp_scte_cc_len++] = cc_data_2;
}
if (!real_count)
{
s->tmp_atsc_cc_len = atsc_cnt_loc;
s->tmp_scte_cc_len = scte_cnt_loc;
}
else
{
s->tmp_atsc_cc_buf[atsc_cnt_loc] = 0x40 | (0x1f&real_count);
s->tmp_atsc_cc_len = atsc_cnt_loc + 2 + 3 * real_count;
s->tmp_scte_cc_buf[scte_cnt_loc] = 0x40 | (0x1f&real_count);
s->tmp_scte_cc_len = scte_cnt_loc + 2 + 3 * real_count;
}
}
} else if (buf_end - p >= 11 &&
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3 changes: 3 additions & 0 deletions mythtv/external/FFmpeg/libavcodec/mpegvideo.c
View file
Expand Up @@ -961,6 +961,9 @@ int MPV_frame_start(MpegEncContext *s, AVCodecContext *avctx)
memcpy(pic->atsc_cc_buf, s->tmp_atsc_cc_buf, s->tmp_atsc_cc_len);
pic->atsc_cc_len = s->tmp_atsc_cc_len;
s->tmp_atsc_cc_len = 0;
memcpy(pic->scte_cc_buf, s->tmp_scte_cc_buf, s->tmp_scte_cc_len);
pic->scte_cc_len = s->tmp_scte_cc_len;
s->tmp_scte_cc_len = 0;

pic->coded_picture_number= s->coded_picture_number++;

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3 changes: 3 additions & 0 deletions mythtv/external/FFmpeg/libavcodec/mpegvideo.h
View file
Expand Up @@ -656,6 +656,9 @@ typedef struct MpegEncContext {
/// frame for these packets has been created in MPV_frame_start().
uint8_t tmp_atsc_cc_buf[ATSC_CC_BUF_SIZE];
int tmp_atsc_cc_len;
#define SCTE_CC_BUF_SIZE 1024
uint8_t tmp_scte_cc_buf[SCTE_CC_BUF_SIZE];
int tmp_scte_cc_len;

int (*decode_mb)(struct MpegEncContext *s, DCTELEM block[6][64]); // used by some codecs to avoid a switch()
#define SLICE_OK 0
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51 changes: 43 additions & 8 deletions mythtv/libs/libmythtv/avformatdecoder.cpp
View file
Expand Up @@ -289,6 +289,9 @@ AvFormatDecoder::AvFormatDecoder(MythPlayer *parent,
special_decode(special_decoding),
maxkeyframedist(-1),
// Closed Caption & Teletext decoders
ignore_scte(false),
invert_scte_field(0),
last_scte_field(0),
ccd608(new CC608Decoder(parent->GetCC608Reader())),
ccd708(new CC708Decoder(parent->GetCC708Reader())),
ttd(new TeletextDecoder(parent->GetTeletextReader())),
Expand Down Expand Up @@ -2483,7 +2486,7 @@ int get_avf_buffer_vaapi(struct AVCodecContext *c, AVFrame *pic)
return 0;
}

void AvFormatDecoder::DecodeDTVCC(const uint8_t *buf, uint len)
void AvFormatDecoder::DecodeDTVCC(const uint8_t *buf, uint len, bool scte)
{
if (!len)
return;
Expand Down Expand Up @@ -2517,13 +2520,36 @@ void AvFormatDecoder::DecodeDTVCC(const uint8_t *buf, uint len)
uint data2 = buf[4+(cur*3)];
uint data = (data2 << 8) | data1;
uint cc_type = cc_code & 0x03;
uint field;

if (cc_type <= 0x1) // EIA-608 field-1/2
if (scte || cc_type <= 0x1) // EIA-608 field-1/2
{
if (cc_type == 0x2)
{
// SCTE repeated field
field = !last_scte_field;
invert_scte_field = !invert_scte_field;
}
else
{
field = cc_type ^ invert_scte_field;
}

// in film mode, we may start at the wrong field;
// correct if XDS is detected (must be field 2)
if (scte && field == 0 && data1 == 0x01)
{
if (cc_type == 1)
invert_scte_field = 0;
field = 1;
}

last_scte_field = field;

if (cc608_good_parity(cc608_parity_table, data))
{
had_608 = true;
ccd608->FormatCCField(lastccptsu / 1000, cc_type, data);
ccd608->FormatCCField(lastccptsu / 1000, field, data);
}
}
else
Expand Down Expand Up @@ -3034,14 +3060,23 @@ bool AvFormatDecoder::ProcessVideoFrame(AVStream *stream, AVFrame *mpa_pic)
{
AVCodecContext *context = stream->codec;

// Decode CEA-608 and CEA-708 captions
for (uint i = 0; i < (uint)mpa_pic->atsc_cc_len;
i += ((mpa_pic->atsc_cc_buf[i] & 0x1f) * 3) + 2)
uint cc_len = (uint) max(mpa_pic->scte_cc_len,0);
uint8_t *cc_buf = mpa_pic->scte_cc_buf;
bool scte = true;

// If both ATSC and SCTE caption data are available, prefer ATSC
if ((mpa_pic->atsc_cc_len > 0) || ignore_scte)
{
DecodeDTVCC(mpa_pic->atsc_cc_buf + i,
mpa_pic->atsc_cc_len - i);
ignore_scte = true;
cc_len = (uint) max(mpa_pic->atsc_cc_len, 0);
cc_buf = mpa_pic->atsc_cc_buf;
scte = false;
}

// Decode CEA-608 and CEA-708 captions
for (uint i = 0; i < cc_len; i += ((cc_buf[i] & 0x1f) * 3) + 2)
DecodeDTVCC(cc_buf + i, cc_len - i, scte);

VideoFrame *picframe = (VideoFrame *)(mpa_pic->opaque);

if (special_decode & kAVSpecialDecode_NoDecode)
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5 changes: 4 additions & 1 deletion mythtv/libs/libmythtv/avformatdecoder.h
View file
Expand Up @@ -203,7 +203,7 @@ class AvFormatDecoder : public DecoderBase
friend int64_t seek_avf(URLContext *h, int64_t offset, int whence);
friend int close_avf(URLContext *h);

void DecodeDTVCC(const uint8_t *buf, uint buf_size);
void DecodeDTVCC(const uint8_t *buf, uint buf_size, bool scte);
void InitByteContext(void);
void InitVideoCodec(AVStream *stream, AVCodecContext *enc,
bool selectedStream = false);
Expand Down Expand Up @@ -311,6 +311,9 @@ class AvFormatDecoder : public DecoderBase
int maxkeyframedist;

// Caption/Subtitle/Teletext decoders
bool ignore_scte;
uint invert_scte_field;
uint last_scte_field;
CC608Decoder *ccd608;
CC708Decoder *ccd708;
TeletextDecoder *ttd;
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16 changes: 14 additions & 2 deletions mythtv/libs/libmythtv/cc608decoder.cpp
View file
Expand Up @@ -176,7 +176,12 @@ void CC608Decoder::FormatCCField(int tc, int field, int data)
}

if (FalseDup(tc, field, data))
goto skip;
{
if (ignore_time_code)
return;
else
goto skip;
}

XDSDecode(field, b1, b2);

Expand Down Expand Up @@ -539,12 +544,19 @@ int CC608Decoder::FalseDup(int tc, int field, int data)

if (ignore_time_code)
{
// just suppress duplicate control codes
// most digital streams with encoded VBI
// have duplicate control codes;
// suppress every other repeated control code
if ((data == lastcode[field]) &&
((b1 & 0x70) == 0x10))
{
lastcode[field] = -1;
return 1;
}
else
{
return 0;
}
}

// bttv-0.9 VBI reads are pretty reliable (1 read/33367us).
Expand Down

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