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Merge branch 'pr/n165_wforums'

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This commit is contained in:
Carlos Fernandez 2015-05-15 08:21:39 -07:00
commit 6a4f379ab7
2 changed files with 96 additions and 42 deletions
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1
src/lib_ccx/lib_ccx.h
View File

@ -350,6 +350,7 @@ void flushbuffer (struct lib_ccx_ctx *ctx, struct ccx_s_write *wb, int closefile
void writercwtdata (struct lib_cc_decode *ctx, const unsigned char *data);
// stream_functions.c
int isValidMP4Box(unsigned char *buffer, long position, long *nextBoxLocation, int *boxScore);
void detect_stream_type (struct lib_ccx_ctx *ctx);
int detect_myth( struct lib_ccx_ctx *ctx );
int read_video_pes_header (struct lib_ccx_ctx *ctx, unsigned char *nextheader, int *headerlength, int sbuflen);

137
src/lib_ccx/stream_functions.c
View File

@ -57,6 +57,37 @@ void detect_stream_type (struct lib_ccx_ctx *ctx)
ctx->startbytes[10]==0)
ctx->stream_mode=CCX_SM_RCWT;
}
if ((ctx->stream_mode == CCX_SM_ELEMENTARY_OR_NOT_FOUND || ccx_options.print_file_reports)
&& ctx->startbytes_avail >= 4) // Still not found
{
long idx = 0, nextBoxLocation = 0, lastBoxLocation = 0;
int boxScore = 0;
// Scan the buffer for valid succeeding MP4 boxes.
while (idx < ctx->startbytes_avail - 7){
lastBoxLocation = idx;
// Check if we have a valid box
if (isValidMP4Box(&ctx->startbytes, idx, &nextBoxLocation, &boxScore))
{
idx = nextBoxLocation; // If the box is valid, a new box should be found on the next location... Not somewhere in between.
if (boxScore > 7)
{
break;
}
continue;
}
else
{
// Not a valid box, reset score. We need a couple of successive boxes to identify a MP4 file.
boxScore = 0;
idx++;
}
}
if (boxScore > 1)
{
// We had at least one box (or multiple) at the end to "claim" this is MP4. A single valid box at the end is doubtful...
ctx->stream_mode = CCX_SM_MP4;
}
}
if (ctx->stream_mode==CCX_SM_ELEMENTARY_OR_NOT_FOUND) // Still not found
{
if (ctx->startbytes_avail > 188*8) // Otherwise, assume no TS
@ -123,48 +154,6 @@ void detect_stream_type (struct lib_ccx_ctx *ctx)
ctx->stream_mode=CCX_SM_ELEMENTARY_OR_NOT_FOUND;
}
}
if ((ctx->stream_mode==CCX_SM_ELEMENTARY_OR_NOT_FOUND || ccx_options.print_file_reports)
&& ctx->startbytes_avail>=4) // Still not found
{
// Try for MP4 by looking for box signatures - this should happen very
// early in the file according to specs
for (int i=0;i<ctx->startbytes_avail-3;i++)
{
// Look for the a box of type 'file'
if (
(ctx->startbytes[i]=='f' && ctx->startbytes[i+1]=='t' &&
ctx->startbytes[i+2]=='y' && ctx->startbytes[i+3]=='p')
||
(ctx->startbytes[i]=='m' && ctx->startbytes[i+1]=='o' &&
ctx->startbytes[i+2]=='o' && ctx->startbytes[i+3]=='v')
||
(ctx->startbytes[i]=='m' && ctx->startbytes[i+1]=='d' &&
ctx->startbytes[i+2]=='a' && ctx->startbytes[i+3]=='t')
||
(ctx->startbytes[i]=='f' && ctx->startbytes[i+1]=='r' &&
ctx->startbytes[i+2]=='e' && ctx->startbytes[i+3]=='e')
||
(ctx->startbytes[i]=='s' && ctx->startbytes[i+1]=='k' &&
ctx->startbytes[i+2]=='i' && ctx->startbytes[i+3]=='p')
||
(ctx->startbytes[i]=='u' && ctx->startbytes[i+1]=='d' &&
ctx->startbytes[i+2]=='t' && ctx->startbytes[i+3]=='a')
||
(ctx->startbytes[i]=='m' && ctx->startbytes[i+1]=='e' &&
ctx->startbytes[i+2]=='t' && ctx->startbytes[i+3]=='a')
||
(ctx->startbytes[i]=='v' && ctx->startbytes[i+1]=='o' &&
ctx->startbytes[i+2]=='i' && ctx->startbytes[i+3]=='d')
||
(ctx->startbytes[i]=='w' && ctx->startbytes[i+1]=='i' &&
ctx->startbytes[i+2]=='d' && ctx->startbytes[i+3]=='e')
)
{
ctx->stream_mode=CCX_SM_MP4;
break;
}
}
}
// Don't use STARTBYTESLENGTH. It might be longer than the file length!
return_to_buffer (ctx->startbytes, ctx->startbytes_avail);
}
@ -405,3 +394,67 @@ int read_video_pes_header (struct lib_ccx_ctx *ctx, unsigned char *nextheader, i
return payloadlength;
}
/*
* Structure for a MP4 box type. Contains the name of the box type and the score we want to assign when a given box type is found.
*/
typedef struct ccx_stream_mp4_box
{
char boxType[5]; // Name of the box structure
int score; // The weight of how heavy a box structure should be counted in order to "recognize" an MP4 file.
} ccx_stream_mp4_box;
/* The box types below are taken from table 1 from ISO/IEC 14496-12_2012 (page 12 and further).
* An asterisk (*) marks a mandatory box for a regular file.
* Box types that are on the second level or deeper are omitted.
*/
ccx_stream_mp4_box ccx_stream_mp4_boxes[11] = {
{ "ftyp", 6 }, // File type and compatibility*
{ "pdin", 1 }, // Progressive download information
{ "moov", 5 }, // Container for all metadata*
{ "moof", 4 }, // Movie fragment
{ "mfra", 3 }, // Movie fragment random access
{ "mdat", 2 }, // Media data container
{ "free", 1 }, // Free space
{ "skip", 1 }, // Free space
{ "meta", 1 }, // Metadata
{ "wide", 1 }, // For boxes that are > 2^32 bytes (https://developer.apple.com/library/mac/documentation/QuickTime/QTFF/QTFFChap1/qtff1.html)
{ "void", 1 } // Unknown where this is from/for, assume free space.
};
/*
* Checks if the buffer, beginning at the given position, contains a valid MP4 box (defined in the ccx_stream_mp4_boxes array).
* If it does contain one, it will set the nextBoxLocation to position + current box size (this should be the place in the buffer
* where the next box should be in case of an mp4) and increment the box score with the defined score for the found box.
*
* Returns 1 when a box is found, 0 when none is found.
*/
int isValidMP4Box(unsigned char *buffer, long position, long *nextBoxLocation, int *boxScore){
for (int idx = 0; idx < 11; idx++){
if (buffer[position + 4] == ccx_stream_mp4_boxes[idx].boxType[0] && buffer[position + 5] == ccx_stream_mp4_boxes[idx].boxType[1] &&
buffer[position + 6] == ccx_stream_mp4_boxes[idx].boxType[2] && buffer[position + 7] == ccx_stream_mp4_boxes[idx].boxType[3]){
mprint("Detected MP4 box with name: %s\n", ccx_stream_mp4_boxes[idx].boxType);
// Box name matches. Do crude validation of possible box size, and if valid, add points for "valid" box
long boxSize = buffer[position] << 24;
boxSize |= buffer[position + 1] << 16;
boxSize |= buffer[position + 2] << 8;
boxSize |= buffer[position + 3];
*boxScore += ccx_stream_mp4_boxes[idx].score;
if (boxSize == 0 || boxSize == 1)
{
// If 0, runs to end of file. If 1, next field contains int_64 containing size, which is definitely bigger than the cache. Both times we can skip further checks by setting
// nextBoxLocation to the max possible.
*nextBoxLocation = UINT32_MAX;
}
else
{
// Set nextBoxLocation to current position + boxSize, as that will be the location of the next box.
*nextBoxLocation = position + boxSize;
}
return 1;
}
}
return 0;
}