//some easy way to get an mpeg4 descriptor ...
GF_EXPORT
GF_Descriptor *gf_odf_desc_new(u8 tag)
{
GF_Descriptor *newdesc;
newdesc = gf_odf_create_descriptor(tag);
newdesc->tag = tag;
return (GF_Descriptor *)newdesc;
}
GF_EXPORT
GF_Err gf_odf_parse_descriptor(GF_BitStream *bs, GF_Descriptor **desc, u32 *desc_size)
{
u32 val, size, sizeHeader;
u8 tag;
GF_Err err;
GF_Descriptor *newDesc;
if (!bs) return GF_BAD_PARAM;
*desc_size = 0;
//tag
tag = (u8) gf_bs_read_int(bs, 8);
sizeHeader = 1;
//size
size = 0;
do {
val = gf_bs_read_int(bs, 8);
sizeHeader++;
size <<= 7;
size |= val & 0x7F;
} while ( val & 0x80);
*desc_size = size;
GF_LOG(GF_LOG_DEBUG, GF_LOG_CODEC, ("[ODF] Reading descriptor (tag %d size %d)\n", tag, size ));
newDesc = gf_odf_create_descriptor(tag);
if (! newDesc) {
*desc = NULL;
*desc_size = sizeHeader;
if ( (tag >= GF_ODF_ISO_RES_BEGIN_TAG) &&
(tag <= GF_ODF_ISO_RES_END_TAG) ) {
return GF_ODF_FORBIDDEN_DESCRIPTOR;
}
else if (!tag || (tag == 0xFF)) {
return GF_ODF_INVALID_DESCRIPTOR;
}
#ifndef GPAC_MINIMAL_ODF
return GF_OUT_OF_MEM;
#else
gf_bs_skip_bytes(bs, size);
*desc_size = size + sizeHeader - gf_odf_size_field_size(*desc_size);
return GF_OK;
#endif
}
newDesc->tag = tag;
err = gf_odf_read_descriptor(bs, newDesc, *desc_size);
/*FFMPEG fix*/
if ((tag==GF_ODF_SLC_TAG) && (((GF_SLConfig*)newDesc)->predefined==2)) {
if (*desc_size==3) {
*desc_size = 1;
err = GF_OK;
}
}
//little trick to handle lazy bitstreams that encode
//SizeOfInstance on a fix number of bytes
//This nb of bytes is added in Read methods
*desc_size += sizeHeader - gf_odf_size_field_size(*desc_size);
*desc = newDesc;
if (err) {
GF_LOG(GF_LOG_ERROR, GF_LOG_CODEC, ("[ODF] Error reading descriptor (tag %d size %d): %s\n", tag, size, gf_error_to_string(err) ));
gf_odf_delete_descriptor(newDesc);
*desc = NULL;
}
return err;
}
