/*
 *			GPAC - Multimedia Framework C SDK
 *
 *			Copyright (c) Jean Le Feuvre 2000-2005 
 *					All rights reserved
 *
 *  This file is part of GPAC / ISO Media File Format sub-project
 *
 *  GPAC 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, or (at your option)
 *  any later version.
 *   
 *  GPAC 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 this library; see the file COPYING.  If not, write to
 *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. 
 *
 */

#include <gpac/internal/isomedia_dev.h>
#include <gpac/constants.h>


#ifndef GPAC_READ_ONLY

GF_Err gf_isom_update_text_description(GF_ISOFile *movie, u32 trackNumber, u32 descriptionIndex, GF_TextSampleDescriptor *desc)
{
	GF_TrackBox *trak;
	GF_Err e;
	u32 i;
	GF_TextSampleEntryBox *txt;

	if (!descriptionIndex || !desc) return GF_BAD_PARAM;
	e = CanAccessMovie(movie, GF_ISOM_OPEN_WRITE);
	if (e) return e;
	
	trak = gf_isom_get_track_from_file(movie, trackNumber);
	if (!trak || !trak->Media || !desc->font_count) return GF_BAD_PARAM;

	if (trak->Media->handler->handlerType != GF_ISOM_MEDIA_TEXT) return GF_BAD_PARAM;

	txt = (GF_TextSampleEntryBox*)gf_list_get(trak->Media->information->sampleTable->SampleDescription->boxList, descriptionIndex - 1);
	if (!txt) return GF_BAD_PARAM;
	if (txt->type != GF_ISOM_BOX_TYPE_TX3G) return GF_BAD_PARAM;

	trak->Media->mediaHeader->modificationTime = gf_isom_get_mp4time();

	txt->back_color = desc->back_color; 
	txt->default_box = desc->default_pos;
	txt->default_style = desc->default_style;
	txt->displayFlags = desc->displayFlags;
	txt->vertical_justification = desc->vert_justif;
	txt->horizontal_justification = desc->horiz_justif;
	if (txt->font_table) gf_isom_box_del((GF_Box*)txt->font_table);

	txt->font_table = (GF_FontTableBox *)gf_isom_box_new(GF_ISOM_BOX_TYPE_FTAB);
	txt->font_table->entry_count = desc->font_count;
	txt->font_table->fonts = (GF_FontRecord *) malloc(sizeof(GF_FontRecord) * desc->font_count);
	for (i=0; i<desc->font_count; i++) {
		txt->font_table->fonts[i].fontID = desc->fonts[i].fontID;
		if (desc->fonts[i].fontName) txt->font_table->fonts[i].fontName = strdup(desc->fonts[i].fontName);
	}
	return e;
}

GF_Err gf_isom_new_text_description(GF_ISOFile *movie, u32 trackNumber, GF_TextSampleDescriptor *desc, char *URLname, char *URNname, u32 *outDescriptionIndex)
{
	GF_TrackBox *trak;
	GF_Err e;
	u32 dataRefIndex, i;
	GF_TextSampleEntryBox *txt;

	e = CanAccessMovie(movie, GF_ISOM_OPEN_WRITE);
	if (e) return e;
	
	trak = gf_isom_get_track_from_file(movie, trackNumber);
	if (!trak || !trak->Media || !desc->font_count) return GF_BAD_PARAM;

	if (trak->Media->handler->handlerType != GF_ISOM_MEDIA_TEXT) return GF_BAD_PARAM;

	//get or create the data ref
	e = Media_FindDataRef(trak->Media->information->dataInformation->dref, URLname, URNname, &dataRefIndex);
	if (e) return e;
	if (!dataRefIndex) {
		e = Media_CreateDataRef(trak->Media->information->dataInformation->dref, URLname, URNname, &dataRefIndex);
		if (e) return e;
	}
	trak->Media->mediaHeader->modificationTime = gf_isom_get_mp4time();

	txt = (GF_TextSampleEntryBox *) gf_isom_box_new(GF_ISOM_BOX_TYPE_TX3G);
	txt->dataReferenceIndex = dataRefIndex;
	gf_list_add(trak->Media->information->sampleTable->SampleDescription->boxList, txt);
	if (outDescriptionIndex) *outDescriptionIndex = gf_list_count(trak->Media->information->sampleTable->SampleDescription->boxList);

	txt->back_color = desc->back_color; 
	txt->default_box = desc->default_pos;
	txt->default_style = desc->default_style;
	txt->displayFlags = desc->displayFlags;
	txt->vertical_justification = desc->vert_justif;
	txt->horizontal_justification = desc->horiz_justif;
	txt->font_table = (GF_FontTableBox *)gf_isom_box_new(GF_ISOM_BOX_TYPE_FTAB);
	txt->font_table->entry_count = desc->font_count;

	txt->font_table->fonts = (GF_FontRecord *) malloc(sizeof(GF_FontRecord) * desc->font_count);
	for (i=0; i<desc->font_count; i++) {
		txt->font_table->fonts[i].fontID = desc->fonts[i].fontID;
		if (desc->fonts[i].fontName) txt->font_table->fonts[i].fontName = strdup(desc->fonts[i].fontName);
	}
	return e;
}


/*blindly adds text - note we don't rely on terminaison characters to handle utf8 and utf16 data 
in the same way. It is the user responsability to signal UTF16*/
GF_Err gf_isom_text_add_text(GF_TextSample *samp, char *text_data, u32 text_len)
{
	if (!samp) return GF_BAD_PARAM;
	if (!text_len) return GF_OK;
	samp->text = (char*)realloc(samp->text, sizeof(char) * (samp->len + text_len) );
	memcpy(samp->text + samp->len, text_data, sizeof(char) * text_len);
	samp->len += text_len;
	return GF_OK;
}

GF_Err gf_isom_text_set_utf16_marker(GF_TextSample *samp)
{
	/*we MUST have an empty sample*/
	if (!samp || samp->text) return GF_BAD_PARAM;
	samp->text = (char*)malloc(sizeof(char) * 2);
	samp->text[0] = (char) 0xFE;
	samp->text[1] = (char) 0xFF;
	samp->len = 2;
	return GF_OK;
}

GF_Err gf_isom_text_add_style(GF_TextSample *samp, GF_StyleRecord *rec)
{
	if (!samp || !rec) return GF_BAD_PARAM;

	if (!samp->styles) {
		samp->styles = (GF_TextStyleBox *) gf_isom_box_new(GF_ISOM_BOX_TYPE_STYL);
		if (!samp->styles) return GF_OUT_OF_MEM;
	}
	samp->styles->styles = (GF_StyleRecord*)realloc(samp->styles->styles, sizeof(GF_StyleRecord)*(samp->styles->entry_count+1));
	if (!samp->styles->styles) return GF_OUT_OF_MEM;
	samp->styles->styles[samp->styles->entry_count] = *rec;
	samp->styles->entry_count++;
	return GF_OK;
}

GF_Err gf_isom_text_add_highlight(GF_TextSample *samp, u16 start_char, u16 end_char)
{
	GF_TextHighlightBox *a;
	if (!samp) return GF_BAD_PARAM;
	if (start_char == end_char) return GF_BAD_PARAM;

	a = (GF_TextHighlightBox *) gf_isom_box_new(GF_ISOM_BOX_TYPE_HLIT);
	if (!a) return GF_OUT_OF_MEM;
	a->startcharoffset = start_char;
	a->endcharoffset = end_char;
	return gf_list_add(samp->others, a);
}

GF_Err gf_isom_text_set_highlight_color(GF_TextSample *samp, u8 r, u8 g, u8 b, u8 a)
{
	if (!samp) return GF_BAD_PARAM;

	if (!samp->highlight_color) {
		samp->highlight_color = (GF_TextHighlightColorBox *) gf_isom_box_new(GF_ISOM_BOX_TYPE_HCLR);
		if (!samp->highlight_color) return GF_OUT_OF_MEM;
	}
	samp->highlight_color->hil_color = a; samp->highlight_color->hil_color <<= 8;
	samp->highlight_color->hil_color = r; samp->highlight_color->hil_color <<= 8;
	samp->highlight_color->hil_color = g; samp->highlight_color->hil_color <<= 8;
	samp->highlight_color->hil_color = b;
	return GF_OK;
}

GF_Err gf_isom_text_set_highlight_color_argb(GF_TextSample *samp, u32 argb)
{
	if (!samp) return GF_BAD_PARAM;

	if (!samp->highlight_color) {
		samp->highlight_color = (GF_TextHighlightColorBox *) gf_isom_box_new(GF_ISOM_BOX_TYPE_HCLR);
		if (!samp->highlight_color) return GF_OUT_OF_MEM;
	}
	samp->highlight_color->hil_color = argb;
	return GF_OK;
}

/*3GPP spec is quite obscur here*/
GF_Err gf_isom_text_add_karaoke(GF_TextSample *samp, u32 start_time)
{
	if (!samp) return GF_BAD_PARAM;
	samp->cur_karaoke = (GF_TextKaraokeBox *) gf_isom_box_new(GF_ISOM_BOX_TYPE_KROK);
	if (!samp->cur_karaoke) return GF_OUT_OF_MEM;
	samp->cur_karaoke->highlight_starttime = start_time;
	return gf_list_add(samp->others, samp->cur_karaoke);
}

GF_Err gf_isom_text_set_karaoke_segment(GF_TextSample *samp, u32 end_time, u16 start_char, u16 end_char)
{
	if (!samp || !samp->cur_karaoke) return GF_BAD_PARAM;
	samp->cur_karaoke->records = (KaraokeRecord*)realloc(samp->cur_karaoke->records, sizeof(KaraokeRecord)*(samp->cur_karaoke->entrycount+1));
	if (!samp->cur_karaoke->records) return GF_OUT_OF_MEM;
	samp->cur_karaoke->records[samp->cur_karaoke->entrycount].end_charoffset = end_char;
	samp->cur_karaoke->records[samp->cur_karaoke->entrycount].start_charoffset = start_char;
	samp->cur_karaoke->records[samp->cur_karaoke->entrycount].highlight_endtime = end_time;
	samp->cur_karaoke->entrycount++;
	return GF_OK;
}


GF_Err gf_isom_text_set_scroll_delay(GF_TextSample *samp, u32 scroll_delay)
{
	if (!samp) return GF_BAD_PARAM;
	if (!samp->scroll_delay) {
		samp->scroll_delay = (GF_TextScrollDelayBox*) gf_isom_box_new(GF_ISOM_BOX_TYPE_DLAY);
		if (!samp->scroll_delay) return GF_OUT_OF_MEM;
	}
	samp->scroll_delay->scroll_delay = scroll_delay;
	return GF_OK;
}

GF_Err gf_isom_text_add_hyperlink(GF_TextSample *samp, char *URL, char *altString, u16 start_char, u16 end_char)
{
	GF_TextHyperTextBox*a;
	if (!samp) return GF_BAD_PARAM;
	a = (GF_TextHyperTextBox*) gf_isom_box_new(GF_ISOM_BOX_TYPE_HREF);
	if (!a) return GF_OUT_OF_MEM;
	a->startcharoffset = start_char;
	a->endcharoffset = end_char;
	a->URL = URL ? strdup(URL) : NULL;
	a->URL_hint = altString ? strdup(altString) : NULL;
	return gf_list_add(samp->others, a);
}

GF_Err gf_isom_text_set_box(GF_TextSample *samp, s16 top, s16 left, s16 bottom, s16 right)
{
	if (!samp) return GF_BAD_PARAM;
	if (!samp->box) {
		samp->box = (GF_TextBoxBox*) gf_isom_box_new(GF_ISOM_BOX_TYPE_TBOX);
		if (!samp->box) return GF_OUT_OF_MEM;
	}
	samp->box->box.top = top;
	samp->box->box.left = left;
	samp->box->box.bottom = bottom;
	samp->box->box.right = right;
	return GF_OK;
}

GF_Err gf_isom_text_add_blink(GF_TextSample *samp, u16 start_char, u16 end_char)
{
	GF_TextBlinkBox *a;
	if (!samp) return GF_BAD_PARAM;
	a = (GF_TextBlinkBox*) gf_isom_box_new(GF_ISOM_BOX_TYPE_BLNK);
	if (!a) return GF_OUT_OF_MEM;
	a->startcharoffset = start_char;
	a->endcharoffset = end_char;
	return gf_list_add(samp->others, a);
}

GF_Err gf_isom_text_set_wrap(GF_TextSample *samp, u8 wrap_flags)
{
	if (!samp) return GF_BAD_PARAM;
	if (!samp->wrap) {
		samp->wrap = (GF_TextWrapBox*) gf_isom_box_new(GF_ISOM_BOX_TYPE_TWRP);
		if (!samp->wrap) return GF_OUT_OF_MEM;
	}
	samp->wrap->wrap_flag = wrap_flags;
	return GF_OK;
}

static GFINLINE GF_Err gpp_write_modifier(GF_BitStream *bs, GF_Box *a)
{
	GF_Err e;
	if (!a) return GF_OK;
	e = gf_isom_box_size(a);
	if (!e) e = gf_isom_box_write(a, bs);
	return e;
}

GF_ISOSample *gf_isom_text_to_sample(GF_TextSample *samp)
{
	GF_Err e;
	GF_ISOSample *res;
	GF_BitStream *bs;
	u32 i;
	if (!samp) return NULL;

	bs = gf_bs_new(NULL, 0, GF_BITSTREAM_WRITE);
	gf_bs_write_u16(bs, samp->len);
	if (samp->len) gf_bs_write_data(bs, samp->text, samp->len);

	e = gpp_write_modifier(bs, (GF_Box *)samp->styles);
	if (!e) e = gpp_write_modifier(bs, (GF_Box *)samp->highlight_color);
	if (!e) e = gpp_write_modifier(bs, (GF_Box *)samp->scroll_delay);
	if (!e) e = gpp_write_modifier(bs, (GF_Box *)samp->box);
	if (!e) e = gpp_write_modifier(bs, (GF_Box *)samp->wrap);

	if (!e) {
		GF_Box *a;
		i=0;
		while ((a = (GF_Box*)gf_list_enum(samp->others, &i))) {
			e = gpp_write_modifier(bs, a);
			if (e) break;
		}
	}
	if (e) {
		gf_bs_del(bs);
		return NULL;
	}
	res = gf_isom_sample_new();
	if (!res) {
		gf_bs_del(bs);
		return NULL;
	}
	gf_bs_get_content(bs, &res->data, &res->dataLength);
	gf_bs_del(bs);
	res->IsRAP = 1;
	return res;
}

GF_Err gf_isom_text_has_similar_description(GF_ISOFile *movie, u32 trackNumber, GF_TextSampleDescriptor *desc, u32 *outDescIdx, Bool *same_box, Bool *same_styles)
{
	GF_TrackBox *trak;
	GF_Err e;
	u32 i, j, count;
	GF_TextSampleEntryBox *txt;

	*same_box = *same_styles = 0;
	*outDescIdx = 0;

	if (!desc) return GF_BAD_PARAM;
	e = CanAccessMovie(movie, GF_ISOM_OPEN_WRITE);
	if (e) return GF_BAD_PARAM;
	
	trak = gf_isom_get_track_from_file(movie, trackNumber);
	if (!trak || !trak->Media || !desc->font_count) return GF_BAD_PARAM;

	if (trak->Media->handler->handlerType != GF_ISOM_MEDIA_TEXT) return GF_BAD_PARAM;

	count = gf_list_count(trak->Media->information->sampleTable->SampleDescription->boxList);
	for (i=0; i<count; i++) {
		Bool same_fonts;
		txt = (GF_TextSampleEntryBox*)gf_list_get(trak->Media->information->sampleTable->SampleDescription->boxList, i);
		if (!txt|| (txt->type != GF_ISOM_BOX_TYPE_TX3G)) continue;
		if (txt->back_color != desc->back_color) continue;
		if (txt->displayFlags != desc->displayFlags) continue;
		if (txt->vertical_justification != desc->vert_justif) continue;
		if (txt->horizontal_justification != desc->horiz_justif) continue;
		if (txt->font_table->entry_count != desc->font_count) continue;

		same_fonts = 1;
		for (j=0; j<desc->font_count; j++) {
			if (txt->font_table->fonts[j].fontID != desc->fonts[j].fontID) same_fonts = 0;
			else if (strcmp(desc->fonts[j].fontName, txt->font_table->fonts[j].fontName)) same_fonts = 0;
		}
		if (same_fonts) {
			*outDescIdx = i+1;
			if (!memcmp(&txt->default_box, &desc->default_pos, sizeof(GF_BoxRecord))) *same_box = 1;
			if (!memcmp(&txt->default_style, &desc->default_style, sizeof(GF_StyleRecord))) *same_styles = 1;
			return GF_OK;
		}
	}
	return GF_OK;
}

#endif

GF_TextSample *gf_isom_new_text_sample()
{
	GF_TextSample *res;
	GF_SAFEALLOC(res, GF_TextSample);
	if (!res) return NULL;
	res->others = gf_list_new();
	return res;
}

GF_Err gf_isom_text_reset_styles(GF_TextSample *samp)
{
	if (!samp) return GF_BAD_PARAM;
	if (samp->box) gf_isom_box_del((GF_Box *)samp->box);
	samp->box = NULL;
	if (samp->highlight_color) gf_isom_box_del((GF_Box *)samp->highlight_color);
	samp->highlight_color = NULL;
	if (samp->scroll_delay) gf_isom_box_del((GF_Box *)samp->scroll_delay);
	samp->scroll_delay = NULL;
	if (samp->wrap) gf_isom_box_del((GF_Box *)samp->wrap);
	samp->wrap = NULL;
	if (samp->styles) gf_isom_box_del((GF_Box *)samp->styles);
	samp->styles = NULL;
	samp->cur_karaoke = NULL;
	while (gf_list_count(samp->others)) {
		GF_Box *a = (GF_Box*)gf_list_get(samp->others, 0);
		gf_list_rem(samp->others, 0);
		gf_isom_box_del(a);
	}
	return GF_OK;
}

GF_Err gf_isom_text_reset(GF_TextSample *samp)
{
	if (!samp) return GF_BAD_PARAM;
	if (samp->text) free(samp->text);
	samp->text = NULL;
	samp->len = 0;
	return gf_isom_text_reset_styles(samp);
}

GF_EXPORT
void gf_isom_delete_text_sample(GF_TextSample * tx_samp)
{
	gf_isom_text_reset(tx_samp);
	gf_list_del(tx_samp->others);
	free(tx_samp);
}

GF_EXPORT
GF_TextSample *gf_isom_parse_texte_sample(GF_BitStream *bs)
{
	GF_TextSample *s = gf_isom_new_text_sample();
	
	/*empty sample*/
	if (!bs || !gf_bs_available(bs)) return s;

	s->len = gf_bs_read_u16(bs);
	if (s->len) {
		/*2 extra bytes for UTF-16 term char just in case (we don't know if a BOM marker is present or 
		not since this may be a sample carried over RTP*/
		s->text = (char *) malloc(sizeof(char)*(s->len+2) );
		s->text[s->len] = 0; s->text[s->len+1] = 0;
		gf_bs_read_data(bs, s->text, s->len);
	}

	while (gf_bs_available(bs)) {
		GF_Box *a;
		GF_Err e = gf_isom_parse_box(&a, bs);
		if (!e) {
			switch (a->type) {
			case GF_ISOM_BOX_TYPE_STYL:
				if (s->styles) {
					GF_TextStyleBox *st2 = (GF_TextStyleBox *)a;
					if (!s->styles->entry_count) {
						gf_isom_box_del((GF_Box*)s->styles);
						s->styles = st2;
					} else {
						s->styles->styles = (GF_StyleRecord*)realloc(s->styles->styles, sizeof(GF_StyleRecord) * (s->styles->entry_count + st2->entry_count));
						memcpy(&s->styles->styles[s->styles->entry_count], st2->styles, sizeof(GF_StyleRecord) * st2->entry_count);
						s->styles->entry_count += st2->entry_count;
						gf_isom_box_del(a);
					}
				} else {
					s->styles = (GF_TextStyleBox*)a;
				}
				break;
			case GF_ISOM_BOX_TYPE_KROK:
				s->cur_karaoke = (GF_TextKaraokeBox*)a;
			case GF_ISOM_BOX_TYPE_HLIT:
			case GF_ISOM_BOX_TYPE_HREF:
			case GF_ISOM_BOX_TYPE_BLNK:
				gf_list_add(s->others, a);
				break;
			case GF_ISOM_BOX_TYPE_HCLR:
				if (s->highlight_color) gf_isom_box_del(a);
				else s->highlight_color = (GF_TextHighlightColorBox *) a;
				break;
			case GF_ISOM_BOX_TYPE_DLAY:
				if (s->scroll_delay) gf_isom_box_del(a);
				else s->scroll_delay= (GF_TextScrollDelayBox*) a;
				break;
			case GF_ISOM_BOX_TYPE_TBOX:
				if (s->box) gf_isom_box_del(a);
				else s->box= (GF_TextBoxBox *) a;
				break;
			case GF_ISOM_BOX_TYPE_TWRP:
				if (s->wrap) gf_isom_box_del(a);
				else s->wrap= (GF_TextWrapBox*) a;
				break;
			default:
				gf_isom_box_del(a);
				break;
			}
		}
	}
	return s;
}

GF_TextSample *gf_isom_parse_texte_sample_from_data(char *data, u32 dataLength)
{
	GF_TextSample *s;
	GF_BitStream *bs;
	/*empty text sample*/
	if (!data || !dataLength) {
		return gf_isom_new_text_sample();
	}
	
	bs = gf_bs_new(data, dataLength, GF_BITSTREAM_READ);
	s = gf_isom_parse_texte_sample(bs);
	gf_bs_del(bs);
	return s;
}


/*out-of-band sample desc (128 and 255 reserved in RFC)*/
#define SAMPLE_INDEX_OFFSET		129


static void gf_isom_write_tx3g(GF_TextSampleEntryBox *a, GF_BitStream *bs, u32 sidx, u32 sidx_offset)
{
	u32 size, j;
	void gpp_write_rgba(GF_BitStream *bs, u32 col);
	void gpp_write_box(GF_BitStream *bs, GF_BoxRecord *rec);
	void gpp_write_style(GF_BitStream *bs, GF_StyleRecord *rec);

	
	if (sidx_offset) gf_bs_write_u8(bs, sidx + sidx_offset);

	/*SINCE WINCE HAS A READONLY VERSION OF MP4 WE MUST DO IT BY HAND*/
	size = 8 + 18 + 8 + 12;
	size += 8 + 2;
	for (j=0; j<a->font_table->entry_count; j++) {
		size += 3;
		if (a->font_table->fonts[j].fontName) size += strlen(a->font_table->fonts[j].fontName);
	}
	/*write TextSampleEntry box*/
	gf_bs_write_u32(bs, size);
	gf_bs_write_u32(bs, GF_ISOM_BOX_TYPE_TX3G);
	gf_bs_write_data(bs, a->reserved, 6);
	gf_bs_write_u16(bs, a->dataReferenceIndex);
	gf_bs_write_u32(bs, a->displayFlags);
	gf_bs_write_u8(bs, a->horizontal_justification);
	gf_bs_write_u8(bs, a->vertical_justification);
	gpp_write_rgba(bs, a->back_color);
	gpp_write_box(bs, &a->default_box);
	gpp_write_style(bs, &a->default_style);
	/*write font table box*/
	size -= (8 + 18 + 8 + 12);
	gf_bs_write_u32(bs, size);
	gf_bs_write_u32(bs, GF_ISOM_BOX_TYPE_FTAB);
	gf_bs_write_u16(bs, a->font_table->entry_count);
	for (j=0; j<a->font_table->entry_count; j++) {
		gf_bs_write_u16(bs, a->font_table->fonts[j].fontID);
		if (a->font_table->fonts[j].fontName) {
			u32 len = strlen(a->font_table->fonts[j].fontName);
			gf_bs_write_u8(bs, len);
			gf_bs_write_data(bs, a->font_table->fonts[j].fontName, len);
		} else {
			gf_bs_write_u8(bs, 0);
		}
	}
}

GF_Err gf_isom_get_ttxt_esd(GF_MediaBox *mdia, GF_ESD **out_esd)
{
	GF_BitStream *bs;
	u32 count, i;
	Bool has_v_info;
	GF_List *sampleDesc;
	GF_ESD *esd;
	GF_TrackBox *tk;

	*out_esd = NULL;
	sampleDesc = mdia->information->sampleTable->SampleDescription->boxList;
	count = gf_list_count(sampleDesc);
	if (!count) return GF_ISOM_INVALID_MEDIA;
	
	esd = gf_odf_desc_esd_new(2);
	esd->decoderConfig->streamType = GF_STREAM_TEXT;
	esd->decoderConfig->objectTypeIndication = 0x08;

	bs = gf_bs_new(NULL, 0, GF_BITSTREAM_WRITE);


	/*Base3GPPFormat*/
	gf_bs_write_u8(bs, 0x10);
	/*MPEGExtendedFormat*/
	gf_bs_write_u8(bs, 0x10);
	/*profileLevel*/
	gf_bs_write_u8(bs, 0x10);
	gf_bs_write_u24(bs, mdia->mediaHeader->timeScale);
	gf_bs_write_int(bs, 0, 1);	/*no alt formats*/
	gf_bs_write_int(bs, 2, 2);	/*only out-of-band-band sample desc*/
	gf_bs_write_int(bs, 1, 1);	/*we will write sample desc*/

	/*write v info if any visual track in this movie*/
	has_v_info = 0;
	i=0;
	while ((tk = (GF_TrackBox*)gf_list_enum(mdia->mediaTrack->moov->trackList, &i))) {
		if (tk->Media->handler && (tk->Media->handler->handlerType == GF_ISOM_MEDIA_VISUAL)) {
			has_v_info = 1;
		}
	}
	gf_bs_write_int(bs, has_v_info, 1);

	gf_bs_write_int(bs, 0, 3);	/*reserved, spec doesn't say the values*/
	gf_bs_write_u8(bs, mdia->mediaTrack->Header->layer);
	gf_bs_write_u16(bs, mdia->mediaTrack->Header->width>>16);
	gf_bs_write_u16(bs, mdia->mediaTrack->Header->height>>16);

	/*write desc*/
	gf_bs_write_u8(bs, count);
	for (i=0; i<count; i++) {
		GF_TextSampleEntryBox *a;
		a = (GF_TextSampleEntryBox *) gf_list_get(sampleDesc, i);
		if (a->type != GF_ISOM_BOX_TYPE_TX3G) continue;
		gf_isom_write_tx3g(a, bs, i+1, SAMPLE_INDEX_OFFSET);
	}
	if (has_v_info) {
		u32 trans;
		/*which video shall we pick for MPEG-4, and how is the associations indicated in 3GP ???*/
		gf_bs_write_u16(bs, 0);
		gf_bs_write_u16(bs, 0);
		trans = mdia->mediaTrack->Header->matrix[6]; trans >>= 16;
		gf_bs_write_u16(bs, trans);
		trans = mdia->mediaTrack->Header->matrix[7]; trans >>= 16;
		gf_bs_write_u16(bs, trans);
	}

	gf_bs_get_content(bs, &esd->decoderConfig->decoderSpecificInfo->data, &esd->decoderConfig->decoderSpecificInfo->dataLength);
	gf_bs_del(bs);
	*out_esd = esd;
	return GF_OK;
}

GF_Err gf_isom_rewrite_text_sample(GF_ISOSample *samp, u32 sampleDescriptionIndex, u32 sample_dur)
{
	GF_BitStream *bs;
	u32 pay_start, txt_size;
	Bool is_utf_16 = 0;
	if (!samp || !samp->data || !samp->dataLength) return GF_OK;

	bs = gf_bs_new(samp->data, samp->dataLength, GF_BITSTREAM_READ);
	txt_size = gf_bs_read_u16(bs);
	gf_bs_del(bs);

	/*remove BOM*/
	pay_start = 2;
	if (txt_size>2) {
		/*seems 3GP only accepts BE UTF-16 (no LE, no UTF32)*/
		if (((u8) samp->data[2]==(u8) 0xFE) && ((u8)samp->data[3]==(u8) 0xFF)) {
			is_utf_16 = 1;
			pay_start = 4;
			txt_size -= 2;
		}
	}

	/*rewrite as TTU(1)*/
	bs = gf_bs_new(NULL, 0, GF_BITSTREAM_WRITE);
	gf_bs_write_int(bs, is_utf_16, 1);
	gf_bs_write_int(bs, 0, 4);
	gf_bs_write_int(bs, 1, 3);
	gf_bs_write_u16(bs, 8 + samp->dataLength - pay_start);
	gf_bs_write_u8(bs, sampleDescriptionIndex + SAMPLE_INDEX_OFFSET);
	gf_bs_write_u24(bs, sample_dur);
	/*write text size*/
	gf_bs_write_u16(bs, txt_size);
	if (txt_size) gf_bs_write_data(bs, samp->data + pay_start, samp->dataLength - pay_start);

	free(samp->data);
	samp->data = NULL;
	gf_bs_get_content(bs, &samp->data, &samp->dataLength);
	gf_bs_del(bs);
	return GF_OK;
}


GF_Err gf_isom_text_get_encoded_tx3g(GF_ISOFile *file, u32 track, u32 sidx, u32 sidx_offset, char **tx3g, u32 *tx3g_size)
{
	GF_BitStream *bs;
	GF_TrackBox *trak;
	GF_TextSampleEntryBox *a;
	
	trak = gf_isom_get_track_from_file(file, track);
	if (!trak) return GF_BAD_PARAM;

	a = (GF_TextSampleEntryBox *) gf_list_get(trak->Media->information->sampleTable->SampleDescription->boxList, sidx-1);
	if (!a || (a->type != GF_ISOM_BOX_TYPE_TX3G)) return GF_BAD_PARAM;
	
	bs = gf_bs_new(NULL, 0, GF_BITSTREAM_WRITE);
	gf_isom_write_tx3g(a, bs, sidx, sidx_offset);
	*tx3g = NULL;
	*tx3g_size = 0;
	gf_bs_get_content(bs, tx3g, tx3g_size);
	gf_bs_del(bs);
	return GF_OK;
}