On Sat, Jan 03, 2015 at 12:57:04PM +0530, Anshul wrote:
> On 01/03/2015 01:42 AM, Michael Niedermayer wrote:
> > On Wed, Dec 31, 2014 at 07:09:33PM +0530, Anshul wrote:
[..]
> Makefile | 1
> allcodecs.c | 1
> ccaption_dec.c | 361
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 363 insertions(+)
> 54d4896ef8724994e1022eec6a9c79d0cddec29d
> 0001-Adding-Closed-caption-Support.patch
> From 17a564409b84fc18293833cc3f2151792209bb8b Mon Sep 17 00:00:00 2001
> From: Anshul Maheshwari <anshul.ffm...@gmail.com>
> Date: Sat, 3 Jan 2015 12:40:35 +0530
> Subject: [PATCH 1/2] Adding Closed caption Support
>
> Signed-off-by: Anshul Maheshwari <anshul.ffm...@gmail.com>
>
> To test Closed caption use following command
> /ffmpeg -f lavfi -i
> "movie=/home/a141982112/test_videos/Starship_Troopers.vob[out0+subcc]" -map s
> some.srt
> ---
> libavcodec/Makefile | 1 +
> libavcodec/allcodecs.c | 1 +
> libavcodec/ccaption_dec.c | 361
> ++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 363 insertions(+)
> create mode 100644 libavcodec/ccaption_dec.c
>
> diff --git a/libavcodec/Makefile b/libavcodec/Makefile
> index 107661b..33051c4 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 8ceee2f..ef77dec 100644
> --- a/libavcodec/allcodecs.c
> +++ b/libavcodec/allcodecs.c
> @@ -481,6 +481,7 @@ 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..d351efe
> --- /dev/null
> +++ b/libavcodec/ccaption_dec.c
> @@ -0,0 +1,361 @@
> +/*
> + * 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"
> +#include "libavutil/opt.h"
> +
> +#undef CHAR_DEBUG
> +#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;
you can use an array here, this would simplify the code and also
avoid the *_FLAG macros
> +};
> +
> +
> +typedef struct CCaptionSubContext {
> + AVClass *class;
> + int parity_table[256];
this can be a static uint8_t table
> + 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];
> + /* buffer to store pkt data */
> + AVBufferRef *pktbuf;
as you memcopy the data each time, theres no need for a AVBufferRef
a simple uint8_t * would do the same
but i think not even that is needed,
all uses of the data go through process_cc608() it would be
very simply to strip one bit in the arguments there, so no rewriting
of the table would be needed
[...]
> +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;
this code appears to lack validity checks on the column index
> + /* reset prev command since character can repeat */
> + ctx->prev_cmd[0] = 0;
> + ctx->prev_cmd[1] = 0;
> +#ifdef CHAR_DEBUG
> + av_log(ctx, AV_LOG_DEBUG,"(%c,%c)\n",hi,lo);
> +#endif
> +}
> +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;
this check appears insufficient to prevent the index fro getting
out of array
rollup can be decresed below row_cnt if iam not missing something
> + ret = handle_edm(ctx, pts);
> + ctx->active_screen = !ctx->active_screen;
> + }
> + } 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 = NULL;
> + int len = avpkt->size;
> + int ret = 0;
> + int i;
> +
> + if ( ctx->pktbuf->size < len) {
> + ret = av_buffer_realloc(&ctx->pktbuf, len);
> + if(ret)
> + len = ctx->pktbuf->size;
> + }
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
Good people do not need laws to tell them to act responsibly, while bad
people will find a way around the laws. -- Plato
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