On 2015-04-13 07:56, Niklesh Lalwani wrote:
From: Niklesh <niklesh.lalw...@iitb.ac.in>
This patch is a part of my qualification task to implement support for
Bold, Italic, and Underlined style records for 3GPP timed text
subtitles. I am continuing Wesley's work. This patch supports decoding
of no more than one style record. Patch[2/2] attempts to use dynamic
arrays to support multiple style records.
Signed-off-by: Niklesh <niklesh.lalw...@iitb.ac.in>
---
libavcodec/movtextdec.c | 81
+++++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 75 insertions(+), 6 deletions(-)
Thank you for posting this.
diff --git a/libavcodec/movtextdec.c b/libavcodec/movtextdec.c
index 1c7ffea..4e463ed 100644
--- a/libavcodec/movtextdec.c
+++ b/libavcodec/movtextdec.c
@@ -26,9 +26,25 @@
#include "libavutil/bprint.h"
#include "libavutil/intreadwrite.h"
-static int text_to_ass(AVBPrint *buf, const char *text, const char
*text_end)
+#define STYLE_FLAG_BOLD 1
+#define STYLE_FLAG_ITALIC 2
+#define STYLE_FLAG_UNDERLINE 4
+
+static int text_to_ass(AVBPrint *buf, const char *text, const char
*text_end,
+ const char *style_start, const char
*style_end,
+ const int style_flags)
{
- while (text < text_end) {
+ while (text < text_end) {
+ if (style_flags && text == style_start)
+ {
+ if (style_flags & STYLE_FLAG_BOLD)
+ av_bprintf(buf, "{\\b1}");
+ if (style_flags & STYLE_FLAG_ITALIC)
+ av_bprintf(buf, "{\\i1}");
+ if (style_flags & STYLE_FLAG_UNDERLINE)
+ av_bprintf(buf, "{\\u1}");
+ }
+
switch (*text) {
case '\r':
break;
@@ -39,6 +55,16 @@ static int text_to_ass(AVBPrint *buf, const char
*text, const char *text_end)
av_bprint_chars(buf, *text, 1);
break;
}
+
+ if (style_flags && text == style_end)
+ {
+ if (style_flags & STYLE_FLAG_BOLD)
+ av_bprintf(buf, "{\\b0}");
+ if (style_flags & STYLE_FLAG_ITALIC)
+ av_bprintf(buf, "{\\i0}");
+ if (style_flags & STYLE_FLAG_UNDERLINE)
+ av_bprintf(buf, "{\\u0}");
+ }
text++;
}
@@ -63,6 +89,9 @@ static int mov_text_decode_frame(AVCodecContext
*avctx,
AVBPrint buf;
const char *ptr = avpkt->data;
const char *end;
+ int text_length, tsmb_type, style_entries, style_flags, tsmb_size;
+ const char *style_start, *style_end;
+ const uint8_t *tsmb;
if (!ptr || avpkt->size < 2)
return AVERROR_INVALIDDATA;
@@ -74,6 +103,7 @@ static int mov_text_decode_frame(AVCodecContext
*avctx,
* already. If the value is non-zero, then it's technically a
* bad packet.
*/
+
if (avpkt->size == 2)
return AV_RB16(ptr) == 0 ? 0 : AVERROR_INVALIDDATA;
@@ -82,7 +112,10 @@ static int mov_text_decode_frame(AVCodecContext
*avctx,
* In complex cases, there are style descriptors appended to the
string
* so we can't just assume the packet size is the string size.
*/
- end = ptr + FFMIN(2 + AV_RB16(ptr), avpkt->size);
+ //end = ptr + FFMIN(2 + AV_RB16(ptr), avpkt->size);
+ text_length = AV_RB16(ptr);
+
+ end = ptr + FFMIN(2 + text_length, avpkt->size);
ptr += 2;
ts_start = av_rescale_q(avpkt->pts,
@@ -91,11 +124,47 @@ static int mov_text_decode_frame(AVCodecContext
*avctx,
ts_end = av_rescale_q(avpkt->pts + avpkt->duration,
avctx->time_base,
(AVRational){1,100});
-
+ tsmb_size=0;
// Note that the spec recommends lines be no longer than 2048
characters.
av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
- text_to_ass(&buf, ptr, end);
- ret = ff_ass_add_rect_bprint(sub, &buf, ts_start,
ts_end-ts_start);
+ if (text_length + 2 != avpkt->size)
+ {
+ while (text_length + 2 + tsmb_size < avpkt->size)
+ {
+ tsmb = ptr + text_length+tsmb_size;
+ tsmb_size = AV_RB32(tsmb);
+ tsmb += 4;
+ tsmb_type = AV_RB32(tsmb);
+ tsmb += 4;
Remember that you need to account for large (> 32bit) boxes here. I
guess it's
almost impossible to get a large box, but it's better to be correct than
to blow
up in the future.
+
+ if (tsmb_type == MKBETAG('s','t','y','l'))
+ {
+ style_entries = AV_RB16(tsmb);
+ tsmb += 2;
+
+ for(int i = 0; i < style_entries;i++)
+ {
+ style_start = ptr + AV_RB16(tsmb);
+ tsmb += 2;
+ style_end = ptr + AV_RB16(tsmb);
+ tsmb += 2;
+ // fontID = AV_RB16(tsmb);
+ tsmb += 2;
+ style_flags = AV_RB8(tsmb);
+ //fontsize=AV_RB8(tsmb);
+ //tsmb += 2;
+ // text-color-rgba
+ //tsmb += 4;
+ text_to_ass(&buf, ptr, end, style_start, style_end,
style_flags);
+ }
As we will be seeing TextModifierStyleBoxes used in multiple places, and
because it's
easier to read, please define and use a struct for it, so you don't have
to do all these
individual reads to access the information. Remember to use a packed
struct or the layout
will not match.
+ }
+
+ }
+ }
+ else
+ text_to_ass(&buf, ptr, end, NULL, NULL, 0);
+
+ ret = ff_ass_add_rect_bprint(sub, &buf, ts_start, ts_end -
ts_start);
av_bprint_finalize(&buf, NULL);
if (ret < 0)
return ret;
--
--phil
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