On 12/06/2014 04:22 PM, Anshul wrote:
> On 12/05/2014 07:56 PM, Nicolas George wrote:
>> Hi. I had time to look at the code with some more details. Comments are
>> below.
>>
>>> >From 31f69ccfb45247a7cc203084a931b8523284aa13 Mon Sep 17 00:00:00 2001
>>> From: Anshul Maheshwari <anshul.ffm...@gmail.com>
>>> Date: Wed, 3 Dec 2014 23:37:22 +0530
>>> Subject: [PATCH 2/2] Adding Closed caption Decoder
>>>
>>> ---
>>> libavcodec/Makefile | 1 +
>>> libavcodec/allcodecs.c | 1 +
>>> libavcodec/ccaption_dec.c | 318
>>> ++++++++++++++++++++++++++++++++++++++++++++++
>>> 3 files changed, 320 insertions(+)
>>> create mode 100644 libavcodec/ccaption_dec.c
>>>
>>> diff --git a/libavcodec/Makefile b/libavcodec/Makefile
>>> index fa0f53d..bbc516d 100644
>>> --- a/libavcodec/Makefile
>>> +++ b/libavcodec/Makefile
>>> @@ -173,6 +173,7 @@ OBJS-$(CONFIG_BRENDER_PIX_DECODER) += brenderpix.o
>>> OBJS-$(CONFIG_C93_DECODER) += c93.o
>>> OBJS-$(CONFIG_CAVS_DECODER) += cavs.o cavsdec.o cavsdsp.o \
>>> cavsdata.o mpeg12data.o
>>> +OBJS-$(CONFIG_CCAPTION_DECODER) += ccaption_dec.o
>>> OBJS-$(CONFIG_CDGRAPHICS_DECODER) += cdgraphics.o
>>> OBJS-$(CONFIG_CDXL_DECODER) += cdxl.o
>>> OBJS-$(CONFIG_CINEPAK_DECODER) += cinepak.o
>>> diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
>>> index 0d39d33..8c07388 100644
>>> --- a/libavcodec/allcodecs.c
>>> +++ b/libavcodec/allcodecs.c
>>> @@ -480,6 +480,7 @@ void avcodec_register_all(void)
>>> /* subtitles */
>>> REGISTER_ENCDEC (SSA, ssa);
>>> REGISTER_ENCDEC (ASS, ass);
>>> + REGISTER_DECODER(CCAPTION, ccaption);
>>> REGISTER_ENCDEC (DVBSUB, dvbsub);
>>> REGISTER_ENCDEC (DVDSUB, dvdsub);
>>> REGISTER_DECODER(JACOSUB, jacosub);
>>> diff --git a/libavcodec/ccaption_dec.c b/libavcodec/ccaption_dec.c
>>> new file mode 100644
>>> index 0000000..0a7dfd8
>>> --- /dev/null
>>> +++ b/libavcodec/ccaption_dec.c
>>> @@ -0,0 +1,318 @@
>>> +/*
>>> + * Closed Caption Decoding
>>> + * Copyright (c) 2014 Anshul Maheshwari
>>> + *
>>> + * This file is part of FFmpeg.
>>> + *
>>> + * FFmpeg is free software; you can redistribute it and/or
>>> + * modify it under the terms of the GNU Lesser General Public
>>> + * License as published by the Free Software Foundation; either
>>> + * version 2.1 of the License, or (at your option) any later version.
>>> + *
>>> + * FFmpeg is distributed in the hope that it will be useful,
>>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
>>> + * Lesser General Public License for more details.
>>> + *
>>> + * You should have received a copy of the GNU Lesser General Public
>>> + * License along with FFmpeg; if not, write to the Free Software
>>> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
>>> 02110-1301 USA
>>> + */
>>> +
>>> +#include "avcodec.h"
>>> +#include "ass.h"
>>> +
>>> +#define SCREEN_ROWS 15
>>> +#define SCREEN_COLUMNS 32
>>> +
>>> +#define SET_FLAG(var, val) ( var |= ( 1 << (val) ) )
>>> +#define UNSET_FLAG(var, val) ( var &= ~( 1 << (val)) )
>>> +#define CHECK_FLAG(var, val) ( (var) & (1 << (val) ) )
>>> +
>>> +enum cc_mode {
>>> + CCMODE_POPON,
>>> + CCMODE_PAINTON,
>>> + CCMODE_ROLLUP_2,
>>> + CCMODE_ROLLUP_3,
>>> + CCMODE_ROLLUP_4,
>>> + CCMODE_TEXT,
>>> +};
>>> +
>>> +struct Screen {
>>> + uint8_t characters[SCREEN_ROWS][SCREEN_COLUMNS+1];
>> Maybe add a comment about the +1?
> done
>>> + /*
>>> + * row used flag will be 0 when none in use other wise it will have its
>>> + * corrosponding bit high.
>> Language nit. I suggest: "Bitmask of used rows; if a bit is not set, the
>> corresponding row is not used."
> done
>>> + * for setting row 1 use row | (1 >> 1)
>>> + * for setting row 15 use row | (1 >> 15)
>> Are you sure that is ">>" and not "<<"? And is it a good idea to number
>> starting from 1?
> It was just commented in wrong way, corrected comment.
>>> + */
>>> + int16_t row_used;
>>> +};
>>> +
>>> +
>>> +typedef struct CCaptionSubContext {
>>> + int parity_table[256];
>>> + int row_cnt;
>>> + struct Screen screen[2];
>>> + int active_screen;
>>> + int cursor_row;
>>> + int cursor_column;
>>> + AVBPrint buffer;
>>> + /* erase display memory */
>>> + int edm;
>> It is used only a handful of times: I suggest a more meaningful name instead
>> of a comment: "erase_disp_mem" for example.
> done
>>> + int rollup;
>>> + enum cc_mode mode;
>>> + int64_t start_time;
>>> + /* visible screen time */
>>> + int64_t startv_time;
>> Is the v a typo?
> no it was written to express v = visible, (visible screen start time)
>>> + int64_t end_time;
>>> + char prev_cmd[2];
>> The code uses various types for these values: char, unsigned char, uint8_t.
>> I suggest to stick with uint8_t if it works.
> changed unsigned char to uint8_t
>>> +}CCaptionSubContext;
>>> +
>>> +static void build_parity_table(int *parity_table)
>>> +{
>>> + unsigned int byte;
>> Inconsistent indentation.
> corrected
>>> + int parity_v;
>>> + for (byte = 0; byte <= 127; byte++) {
>>> + parity_v = av_popcount(byte & 0x7f) & 1;
>> The & 0x7f is redundant.
> removed
>>> + parity_table[byte] = parity_v;
>>> + parity_table[byte | 0x80] = !parity_v;
>>> + }
>>> +}
>>> +
>>> +static av_cold int init_decoder(AVCodecContext *avctx)
>>> +{
>>> +
>>> + CCaptionSubContext *ctx = avctx->priv_data;
>>> +
>>> + build_parity_table(ctx->parity_table);
>>> + ctx->row_cnt = 0;
>>> + av_bprint_init(&ctx->buffer, 0, AV_BPRINT_SIZE_UNLIMITED);
>>> + ctx->edm = 0;
>>> + /* taking by default roll up to 2 */
>>> + ctx->rollup = 2;
>>> + /* set active screen as 0 */
>>> + ctx->active_screen = 0;
>>> + memset(ctx->prev_cmd,0,2);
>>> + ff_ass_subtitle_header_default(avctx);
>> All the "= 0" and the memset are unnecessary.
> removed
>>> + return 0;
>>> +}
>>> +
>>> +static av_cold int close_decoder(AVCodecContext *avctx)
>>> +{
>>> + CCaptionSubContext *ctx = avctx->priv_data;
>>> + av_bprint_finalize( &ctx->buffer, NULL);
>>> + return 0;
>>> +}
>>> +
>>> +/**
>>> + * This function after validating parity bit, also remove it from data
>>> pair.
>>> + */
>>> +static int validate_cc_data_pair (unsigned char *cc_data_pair, int
>>> *parity_table)
>>> +{
>>> + unsigned char cc_valid = (*cc_data_pair & 4) >>2;
>>> + unsigned char cc_type = *cc_data_pair & 3;
>>> +
>>> + if (!cc_valid)
>>> + return -1;
>>> +
>>> + // if EIA-608 data then verify parity.
>>> + if (cc_type==0 || cc_type==1) {
>>> + if (!parity_table[cc_data_pair[2]]) {
>>> + // If the second byte doesn't pass parity, ignore pair
>>> + return -1;
>> Meaningful error codes? AVERROR(EINVAL) or AVERROR_INVALID_DATA? Even when
>> they are not supposed to, the -1 have a habit of reaching the user. Same
>> below.
> done
>>> + }
>>> + if (!parity_table[cc_data_pair[1]]) {
>>> + // The first byte doesn't pass parity, we replace it with a solid
>>> blank
>>> + // and process the pair.
>>> + cc_data_pair[1]=0x7F;
>>> + }
>>> + }
>>> +
>>> + //Skip non-data
>>> + if( (cc_data_pair[0] == 0xFA || cc_data_pair[0] == 0xFC ||
>>> cc_data_pair[0] == 0xFD )
>>> + && (cc_data_pair[1] & 0x7F) == 0 && (cc_data_pair[2] & 0x7F) == 0)
>>> + return -1;
>>> +
>>> + //skip 708 data
>>> + if(cc_type == 3 || cc_type == 2 )
>>> + return -1;
>>> +
>>> + /* remove parity bit */
>>> + cc_data_pair[1] &= 0x7F;
>>> + cc_data_pair[2] &= 0x7F;
>>> +
>>> +
>>> + return 0;
>>> +
>>> +}
>>> +static void handle_pac( CCaptionSubContext *ctx, uint8_t hi, uint8_t lo )
>>> +{
>>> + static const int row_map[] = {
>> Could be int8_t to save memory.
> done
>>> + 11, -1, 1, 2, 3, 4, 12, 13, 14, 15, 5, 6, 7, 8, 9, 10
>>> + };
>>> + const int index = ( (hi<<1) & 0x0e) | ( (lo>>5) & 0x01 );
>>> +
>> It looks like the values come from external data with subtle arithmetic, so
>> I suggest:
>>
>> av_assert2((unsigned)index < sizeof(row_map));
> I am using 3 bit from hi and 1 bit from lo data, so I am using total 4 bit
> which mean only 0-15 possible. and for unknown value not defined in spec
> I have kept the value as -1 on that index.
> so no need to check.
>>> + if( row_map[index] <= 0 )
>>> + return;
>>> +
>>> + ctx->cursor_row = row_map[index] - 1;
>>> + ctx->cursor_column = 0;
>>> +
>>> +}
>>> +
>>> +/**
>>> + * @param pts it is required to set end time
>>> + */
>>> +static void handle_edm(CCaptionSubContext *ctx,int64_t pts)
>>> +{
>>> + int i;
>>> + struct Screen *screen = ctx->screen + ctx->active_screen;
>>> +
>>> + ctx->start_time = ctx->startv_time;
>>> + for( i = 0; screen->row_used && i < SCREEN_ROWS; i++)
>>> + {
>>> + if(CHECK_FLAG(screen->row_used,i)) {
>>> + av_bprint_append_data(&ctx->buffer, screen->characters[i],
>>> strlen(screen->characters[i]));
>>> + av_bprint_append_data(&ctx->buffer, "\\N",2);
>>> + UNSET_FLAG(screen->row_used, i);
>>> + }
>>> + }
>>> + ctx->startv_time = pts;
>>> + ctx->edm = 1;
>>> + ctx->end_time = pts;
>>> +}
>>> +static void handle_eoc(CCaptionSubContext *ctx, int64_t pts)
>>> +{
>>> + ctx->active_screen = !ctx->active_screen;
>>> + ctx->startv_time = pts;
>>> +}
>>> +static struct Screen *get_writing_screen(CCaptionSubContext *ctx)
>>> +{
>>> + switch (ctx->mode) {
>>> + case CCMODE_POPON:
>>> + // use Inactive screen
>>> + return ctx->screen + !ctx->active_screen;
>>> + case CCMODE_PAINTON:
>>> + case CCMODE_ROLLUP_2:
>>> + case CCMODE_ROLLUP_3:
>>> + case CCMODE_ROLLUP_4:
>>> + case CCMODE_TEXT:
>>> + // use active screen
>>> + return ctx->screen + !ctx->active_screen;
>>> + }
>>> + /* It was never an option */
>>> + return NULL;
>>> +}
>>> +static void handle_char(CCaptionSubContext *ctx, char hi, char lo, int64_t
>>> pts)
>>> +{
>>> + struct Screen *screen = get_writing_screen(ctx);
>>> + char *row = screen->characters[ctx->cursor_row] + ctx->cursor_column;
>> Here too: av_assert0((unsigned)ctx->cursor_row < SCREEN_ROWS) and same for
>> column.
> We can never get row greater then SCREEN_ROWS, I have not implemented to
> read column value from pac. so left it as it is.
>>> +
>>> + SET_FLAG(screen->row_used,ctx->cursor_row);
>>> +
>>> + *row++ = hi;
>>> + ctx->cursor_column++;
>>> + if(lo) {
>>> + *row++ = lo;
>>> + ctx->cursor_column++;
>>> + }
>>> + *row = 0;
>>> + /* reset prev command since character can repeat */
>>> + ctx->prev_cmd[0] = 0;
>>> + ctx->prev_cmd[1] = 0;
>>> +}
>>> +static int process_cc608(CCaptionSubContext *ctx, int64_t pts, unsigned
>>> char hi, unsigned char lo)
>>> +{
>>> +
>>> +#define COR3(var, with1, with2, with3) ( (var) == (with1) || (var) ==
>>> (with2) || (var) == (with3) )
>> It looks like you always use COR3(hi, 0x14, 0x15, 0x1C) exactly: is it on
>> purpose, a typo, or maybe can you simplify?
> These are done for purpose, I have to implement some other command which
> have
> different values to be compared. so not simplifying it.
>>> + if ( hi == ctx->prev_cmd[0] && lo == ctx->prev_cmd[1]) {
>>> + /* ignore redundant command */
>>> + } else if ( (hi == 0x10 && (lo >= 0x40 || lo <= 0x5f)) ||
>>> + ( (hi >= 0x11 && hi <= 0x17) && (lo >= 0x40 && lo <= 0x7f) )
>>> ) {
>>> + handle_pac(ctx, hi, lo);
>>> + } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x20 ) {
>>> + /* resume caption loading */
>>> + ctx->mode = CCMODE_POPON;
>>> + } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x25 ) {
>>> + ctx->rollup = 2;
>>> + } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x26 ) {
>>> + ctx->rollup = 3;
>>> + } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x27 ) {
>>> + ctx->rollup = 4;
>>> + } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x29 ) {
>>> + /* resume direct captioning */
>>> + ctx->mode = CCMODE_PAINTON;
>>> + } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x2C ) {
>>> + /* erase display memory */
>>> + handle_edm(ctx, pts);
>>> + } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x2D ) {
>>> + /* carriage return */
>>> + ctx->row_cnt++;
>>> + if(ctx->row_cnt == ctx->rollup) {
>>> + ctx->row_cnt = 0;
>>> + handle_edm(ctx, pts);
>>> + }
>>> + } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x2F ) {
>>> + /* end of caption */
>>> + handle_eoc(ctx, pts);
>>> + } else if (hi>=0x20) {
>>> + /* Standard characters (always in pairs) */
>>> + handle_char(ctx, hi, lo, pts);
>>> + } else {
>>> + /* Ignoring all other non data code */
>>> + }
>>> +
>>> + /* set prev command */
>>> + ctx->prev_cmd[0] = hi;
>>> + ctx->prev_cmd[1] = lo;
>>> +
>>> +#undef COR3
>>> + return 0;
>>> +
>>> +}
>>> +static int decode(AVCodecContext *avctx, void *data, int *got_sub,
>>> AVPacket *avpkt)
>>> +{
>>> + CCaptionSubContext *ctx = avctx->priv_data;
>>> + AVSubtitle *sub = data;
>>> + unsigned char *bptr = avpkt->data;
>>> + int len = avpkt->size;
>>> + int ret = 0;
>>> + int i;
>>> +
>>> + for (i = 0; i < len; i += 3) {
>>> + unsigned char cc_type = *(bptr + i) & 3;
>>> + if (validate_cc_data_pair( bptr + i, ctx->parity_table ) )
>>> + continue;
>>> + /* ignoring data field 1 */
>>> + if(cc_type == 1)
>>> + continue;
>>> + else
>>> + process_cc608(ctx, avpkt->pts, *(bptr + i + 1), *(bptr + i +
>>> 2));
>>> + }
>>> + if(ctx->edm && *ctx->buffer.str)
>>> + {
>>> + int start_time = av_rescale_q(ctx->start_time, avctx->time_base,
>>> (AVRational){ 1, 100 });
>>> + int end_time = av_rescale_q(ctx->end_time, avctx->time_base,
>>> (AVRational){ 1, 100 });
>>> + ret = ff_ass_add_rect(sub, ctx->buffer.str, start_time, end_time -
>>> start_time , 0);
>>> a
>> You need to use av_bprint_is_complete() and return AVERROR(ENOMEM) if the
>> text was truncated.
> done in handle_edm
>>> + if (ret < 0)
>>> + return ret;
>>> + sub->pts = av_rescale_q(ctx->start_time, avctx->time_base,
>>> AV_TIME_BASE_Q);
>>> + ctx->edm = 0;
>>> + av_bprint_clear(&ctx->buffer);
>>> + }
>>> +
>>> + *got_sub = sub->num_rects > 0;
>>> + return 0;
>>> +}
>>> +
>>> +AVCodec ff_ccaption_decoder = {
>>> + .name = "cc_dec",
>>> + .long_name = NULL_IF_CONFIG_SMALL("Closed Caption Decoder"),
>> I suggest to have "EIA-608" and "CEA-708" appear in the name, for people
>> specifically looking for it: "Closed Caption (EIA-608 / CEA-708) Decoder"
>> maybe.
> done
>>> + .type = AVMEDIA_TYPE_SUBTITLE,
>>> + .id = AV_CODEC_ID_EIA_608,
>>> + .priv_data_size = sizeof(CCaptionSubContext),
>>> + .init = init_decoder,
>>> + .close = close_decoder,
>>> + .decode = decode,
>>> +};
>> Regards,
>>
> I have also removed some error which were causing to print nothing in
> subccItalic.mpg.
>
> Though subtitle is still not italic.
>
> I was thinking to put extra features in next iteration of patch.
>
> -Anshul
>
Attaching patch with those work.
>From 0c827d7619da208a6080955779712199de62f202 Mon Sep 17 00:00:00 2001
From: Anshul Maheshwari <anshul.ffm...@gmail.com>
Date: Sat, 6 Dec 2014 16:06:32 +0530
Subject: [PATCH] Adding closed caption decoder
---
libavcodec/Makefile | 1 +
libavcodec/allcodecs.c | 1 +
libavcodec/ccaption_dec.c | 324 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 326 insertions(+)
create mode 100644 libavcodec/ccaption_dec.c
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 1a0072a..b35a796 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -169,6 +169,7 @@ OBJS-$(CONFIG_BRENDER_PIX_DECODER) += brenderpix.o
OBJS-$(CONFIG_C93_DECODER) += c93.o
OBJS-$(CONFIG_CAVS_DECODER) += cavs.o cavsdec.o cavsdsp.o \
cavsdata.o mpeg12data.o
+OBJS-$(CONFIG_CCAPTION_DECODER) += ccaption_dec.o
OBJS-$(CONFIG_CDGRAPHICS_DECODER) += cdgraphics.o
OBJS-$(CONFIG_CDXL_DECODER) += cdxl.o
OBJS-$(CONFIG_CINEPAK_DECODER) += cinepak.o
diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
index d08abd8..36bbfed 100644
--- a/libavcodec/allcodecs.c
+++ b/libavcodec/allcodecs.c
@@ -479,6 +479,7 @@ void avcodec_register_all(void)
/* subtitles */
REGISTER_ENCDEC (SSA, ssa);
REGISTER_ENCDEC (ASS, ass);
+ REGISTER_DECODER(CCAPTION, ccaption);
REGISTER_ENCDEC (DVBSUB, dvbsub);
REGISTER_ENCDEC (DVDSUB, dvdsub);
REGISTER_DECODER(JACOSUB, jacosub);
diff --git a/libavcodec/ccaption_dec.c b/libavcodec/ccaption_dec.c
new file mode 100644
index 0000000..d42f376
--- /dev/null
+++ b/libavcodec/ccaption_dec.c
@@ -0,0 +1,324 @@
+/*
+ * Closed Caption Decoding
+ * Copyright (c) 2014 Anshul Maheshwari
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "avcodec.h"
+#include "ass.h"
+
+#define SCREEN_ROWS 15
+#define SCREEN_COLUMNS 32
+
+#define SET_FLAG(var, val) ( var |= ( 1 << (val) ) )
+#define UNSET_FLAG(var, val) ( var &= ~( 1 << (val)) )
+#define CHECK_FLAG(var, val) ( (var) & (1 << (val) ) )
+
+enum cc_mode {
+ CCMODE_POPON,
+ CCMODE_PAINTON,
+ CCMODE_ROLLUP_2,
+ CCMODE_ROLLUP_3,
+ CCMODE_ROLLUP_4,
+ CCMODE_TEXT,
+};
+
+struct Screen {
+ /* +1 is used to compensate null character of string */
+ uint8_t characters[SCREEN_ROWS][SCREEN_COLUMNS+1];
+ /*
+ * Bitmask of used rows; if a bit is not set, the
+ * corresponding row is not used.
+ * for setting row 1 use row | (0 << 1)
+ * for setting row 15 use row | (1 << 14)
+ */
+ int16_t row_used;
+};
+
+
+typedef struct CCaptionSubContext {
+ int parity_table[256];
+ int row_cnt;
+ struct Screen screen[2];
+ int active_screen;
+ uint8_t cursor_row;
+ uint8_t cursor_column;
+ AVBPrint buffer;
+ int erase_display_memory;
+ int rollup;
+ enum cc_mode mode;
+ int64_t start_time;
+ /* visible screen time */
+ int64_t startv_time;
+ int64_t end_time;
+ char prev_cmd[2];
+}CCaptionSubContext;
+
+static void build_parity_table(int *parity_table)
+{
+ unsigned int byte;
+ int parity_v;
+ for (byte = 0; byte <= 127; byte++) {
+ parity_v = av_popcount(byte) & 1;
+ parity_table[byte] = parity_v;
+ parity_table[byte | 0x80] = !parity_v;
+ }
+}
+
+static av_cold int init_decoder(AVCodecContext *avctx)
+{
+ int ret;
+ CCaptionSubContext *ctx = avctx->priv_data;
+
+ build_parity_table(ctx->parity_table);
+ av_bprint_init(&ctx->buffer, 0, AV_BPRINT_SIZE_UNLIMITED);
+ /* taking by default roll up to 2 */
+ ctx->rollup = 2;
+ ret = ff_ass_subtitle_header_default(avctx);
+
+ return ret;
+}
+
+static av_cold int close_decoder(AVCodecContext *avctx)
+{
+ CCaptionSubContext *ctx = avctx->priv_data;
+ av_bprint_finalize( &ctx->buffer, NULL);
+ return 0;
+}
+
+/**
+ * This function after validating parity bit, also remove it from data pair.
+ */
+static int validate_cc_data_pair (uint8_t *cc_data_pair, int *parity_table)
+{
+ uint8_t cc_valid = (*cc_data_pair & 4) >>2;
+ uint8_t cc_type = *cc_data_pair & 3;
+
+ if (!cc_valid)
+ return AVERROR_INVALIDDATA;
+
+ // if EIA-608 data then verify parity.
+ if (cc_type==0 || cc_type==1) {
+ if (!parity_table[cc_data_pair[2]]) {
+ // If the second byte doesn't pass parity, ignore pair
+ return AVERROR_INVALIDDATA;
+ }
+ if (!parity_table[cc_data_pair[1]]) {
+ // The first byte doesn't pass parity, we replace it with a solid blank
+ // and process the pair.
+ cc_data_pair[1]=0x7F;
+ }
+ }
+
+ //Skip non-data
+ if( (cc_data_pair[0] == 0xFA || cc_data_pair[0] == 0xFC || cc_data_pair[0] == 0xFD )
+ && (cc_data_pair[1] & 0x7F) == 0 && (cc_data_pair[2] & 0x7F) == 0)
+ return AVERROR_PATCHWELCOME;
+
+ //skip 708 data
+ if(cc_type == 3 || cc_type == 2 )
+ return AVERROR_PATCHWELCOME;
+
+ /* remove parity bit */
+ cc_data_pair[1] &= 0x7F;
+ cc_data_pair[2] &= 0x7F;
+
+
+ return 0;
+
+}
+static void handle_pac( CCaptionSubContext *ctx, uint8_t hi, uint8_t lo )
+{
+ static const uint8_t row_map[] = {
+ 11, -1, 1, 2, 3, 4, 12, 13, 14, 15, 5, 6, 7, 8, 9, 10
+ };
+ const int index = ( (hi<<1) & 0x0e) | ( (lo>>5) & 0x01 );
+
+ if( row_map[index] <= 0 )
+ return;
+
+ ctx->cursor_row = row_map[index] - 1;
+ ctx->cursor_column = 0;
+
+}
+
+/**
+ * @param pts it is required to set end time
+ */
+static int handle_edm(CCaptionSubContext *ctx,int64_t pts)
+{
+ int i;
+ int ret = 0;
+ struct Screen *screen = ctx->screen + ctx->active_screen;
+
+ ctx->start_time = ctx->startv_time;
+ for( i = 0; screen->row_used && i < SCREEN_ROWS; i++)
+ {
+ if(CHECK_FLAG(screen->row_used,i)) {
+ av_bprint_append_data(&ctx->buffer, screen->characters[i], strlen(screen->characters[i]));
+ av_bprint_append_data(&ctx->buffer, "\\N",2);
+ UNSET_FLAG(screen->row_used, i);
+ ret = av_bprint_is_complete(&ctx->buffer);
+ if( ret) {
+ ret = AVERROR(ENOMEM);
+ break;
+ }
+ }
+
+ }
+ ctx->startv_time = pts;
+ ctx->erase_display_memory = 1;
+ ctx->end_time = pts;
+ return ret;
+}
+static int handle_eoc(CCaptionSubContext *ctx, int64_t pts)
+{
+ int ret;
+ ret = handle_edm(ctx,pts);
+ ctx->active_screen = !ctx->active_screen;
+ return ret;
+}
+static struct Screen *get_writing_screen(CCaptionSubContext *ctx)
+{
+ switch (ctx->mode) {
+ case CCMODE_POPON:
+ // use Inactive screen
+ return ctx->screen + !ctx->active_screen;
+ case CCMODE_PAINTON:
+ case CCMODE_ROLLUP_2:
+ case CCMODE_ROLLUP_3:
+ case CCMODE_ROLLUP_4:
+ case CCMODE_TEXT:
+ // use active screen
+ return ctx->screen + !ctx->active_screen;
+ }
+ /* It was never an option */
+ return NULL;
+}
+static void handle_char(CCaptionSubContext *ctx, char hi, char lo, int64_t pts)
+{
+ struct Screen *screen = get_writing_screen(ctx);
+ char *row = screen->characters[ctx->cursor_row] + ctx->cursor_column;
+
+ SET_FLAG(screen->row_used,ctx->cursor_row);
+
+ *row++ = hi;
+ ctx->cursor_column++;
+ if(lo) {
+ *row++ = lo;
+ ctx->cursor_column++;
+ }
+ *row = 0;
+ /* reset prev command since character can repeat */
+ ctx->prev_cmd[0] = 0;
+ ctx->prev_cmd[1] = 0;
+}
+static int process_cc608(CCaptionSubContext *ctx, int64_t pts, uint8_t hi, uint8_t lo)
+{
+ int ret = 0;
+#define COR3(var, with1, with2, with3) ( (var) == (with1) || (var) == (with2) || (var) == (with3) )
+ if ( hi == ctx->prev_cmd[0] && lo == ctx->prev_cmd[1]) {
+ /* ignore redundant command */
+ } else if ( (hi == 0x10 && (lo >= 0x40 || lo <= 0x5f)) ||
+ ( (hi >= 0x11 && hi <= 0x17) && (lo >= 0x40 && lo <= 0x7f) ) ) {
+ handle_pac(ctx, hi, lo);
+ } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x20 ) {
+ /* resume caption loading */
+ ctx->mode = CCMODE_POPON;
+ } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x25 ) {
+ ctx->rollup = 2;
+ } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x26 ) {
+ ctx->rollup = 3;
+ } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x27 ) {
+ ctx->rollup = 4;
+ } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x29 ) {
+ /* resume direct captioning */
+ ctx->mode = CCMODE_PAINTON;
+ } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x2C ) {
+ /* erase display memory */
+ ret = handle_edm(ctx, pts);
+ } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x2D ) {
+ /* carriage return */
+ ctx->row_cnt++;
+ if(ctx->row_cnt == ctx->rollup) {
+ ctx->row_cnt = 0;
+ ret = handle_edm(ctx, pts);
+ }
+ } else if ( COR3(hi, 0x14, 0x15, 0x1C) && lo == 0x2F ) {
+ /* end of caption */
+ ret = handle_eoc(ctx, pts);
+ } else if (hi>=0x20) {
+ /* Standard characters (always in pairs) */
+ handle_char(ctx, hi, lo, pts);
+ } else {
+ /* Ignoring all other non data code */
+ }
+
+ /* set prev command */
+ ctx->prev_cmd[0] = hi;
+ ctx->prev_cmd[1] = lo;
+
+#undef COR3
+ return ret;
+
+}
+static int decode(AVCodecContext *avctx, void *data, int *got_sub, AVPacket *avpkt)
+{
+ CCaptionSubContext *ctx = avctx->priv_data;
+ AVSubtitle *sub = data;
+ uint8_t *bptr = avpkt->data;
+ int len = avpkt->size;
+ int ret = 0;
+ int i;
+
+ for (i = 0; i < len; i += 3) {
+ uint8_t cc_type = *(bptr + i) & 3;
+ if (validate_cc_data_pair( bptr + i, ctx->parity_table ) )
+ continue;
+ /* ignoring data field 1 */
+ if(cc_type == 1)
+ continue;
+ else
+ process_cc608(ctx, avpkt->pts, *(bptr + i + 1), *(bptr + i + 2));
+ }
+ if(ctx->erase_display_memory && *ctx->buffer.str)
+ {
+ int start_time = av_rescale_q(ctx->start_time, avctx->time_base, (AVRational){ 1, 100 });
+ int end_time = av_rescale_q(ctx->end_time, avctx->time_base, (AVRational){ 1, 100 });
+ ret = ff_ass_add_rect(sub, ctx->buffer.str, start_time, end_time - start_time , 0);
+ if (ret < 0)
+ return ret;
+ sub->pts = av_rescale_q(ctx->start_time, avctx->time_base, AV_TIME_BASE_Q);
+ ctx->erase_display_memory = 0;
+ av_bprint_clear(&ctx->buffer);
+ }
+
+ *got_sub = sub->num_rects > 0;
+ return 0;
+}
+
+AVCodec ff_ccaption_decoder = {
+ .name = "cc_dec",
+ .long_name = NULL_IF_CONFIG_SMALL("Closed Caption (EIA-608 / CEA-708) Decoder"),
+ .type = AVMEDIA_TYPE_SUBTITLE,
+ .id = AV_CODEC_ID_EIA_608,
+ .priv_data_size = sizeof(CCaptionSubContext),
+ .init = init_decoder,
+ .close = close_decoder,
+ .decode = decode,
+};
--
1.8.1.4
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