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qt-faststart: speedup 

qt-faststart is terribly slow when the input file and the output file
are on a slow disk like a SD card. By increasing the copy_buffer from
1K to 32M I decreased the processing time on a sample file from
1600 seconds to 4 seconds. The timing difference is during 'copying
rest of file'.

S:\SD_VIDEO\PRG001>e:\utils\qt-faststart 00005.mp4 5.mp4
ftyp          0 32
free         32 8
mdat         40 13744391
moov   13744431 141848
 patching stco atom...
 patching stco atom...
 writing ftyp atom...
 writing moov atom...
 copying rest of file...

Execution time: 1576.259 s

S:\SD_VIDEO\PRG001>s:\utils\qt-faststart 00005.mp4 5.mp4
ftyp          0 32
free         32 8
mdat         40 13744391
moov   13744431 141848
 patching stco atom...
 patching stco atom...
 writing ftyp atom...
 writing moov atom...
 copying rest of file...

Execution time: 3.846 s

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Jan Ehrhardt 2012-09-30 21:32:26 +02:00 committed by Michael Niedermayer
parent 13d878366f
commit f4d9148fe2
1 changed files with 9 additions and 2 deletions
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11
tools/qt-faststart.c
View File

@ -77,7 +77,7 @@
#define CO64_ATOM QT_ATOM('c', 'o', '6', '4')
#define ATOM_PREAMBLE_SIZE 8
#define COPY_BUFFER_SIZE 1024
#define COPY_BUFFER_SIZE 33554432
int main(int argc, char *argv[])
{
@ -96,7 +96,7 @@ int main(int argc, char *argv[])
uint32_t offset_count;
uint64_t current_offset;
uint64_t start_offset = 0;
unsigned char copy_buffer[COPY_BUFFER_SIZE];
unsigned char *copy_buffer = NULL;
int bytes_to_copy;
if (argc != 3) {
@ -293,6 +293,11 @@ int main(int argc, char *argv[])
}
/* copy the remainder of the infile, from offset 0 -> last_offset - 1 */
copy_buffer = malloc(COPY_BUFFER_SIZE);
if (!copy_buffer) {
printf("could not allocate %"PRIu64" bytes for copy_buffer\n", COPY_BUFFER_SIZE);
goto error_out;
}
printf(" copying rest of file...\n");
while (last_offset) {
if (last_offset > COPY_BUFFER_SIZE)
@ -315,6 +320,7 @@ int main(int argc, char *argv[])
fclose(outfile);
free(moov_atom);
free(ftyp_atom);
free(copy_buffer);
return 0;
@ -325,5 +331,6 @@ error_out:
fclose(outfile);
free(moov_atom);
free(ftyp_atom);
free(copy_buffer);
return 1;
}