On Tue, May 29, 2018 at 02:36:28PM +0000, Eran Kornblau wrote: > Hi, > > The attached is a slightly more optimized (and IMHO elegant) code for > updating the stco/co64 offsets > > Thanks > > Eran
> qt-faststart.c | 42 +++++++++++++++++++++++++-----------------
> 1 file changed, 25 insertions(+), 17 deletions(-)
> a0f95e960800141a0a666313f2f3d82a87a3309f
> 0002-qt-faststart-optimize-the-offset-change-loop.patch
> From 776244b79a8bcfb5732f39fbebb9cd7fc0092bcb Mon Sep 17 00:00:00 2001
> From: erankor <eran.kornb...@kaltura.com>
> Date: Tue, 29 May 2018 17:29:09 +0300
> Subject: [PATCH 2/2] qt-faststart - optimize the offset change loop
>
> ---
> tools/qt-faststart.c | 42 +++++++++++++++++++++++++-----------------
> 1 file changed, 25 insertions(+), 17 deletions(-)
>
> diff --git a/tools/qt-faststart.c b/tools/qt-faststart.c
> index d0ae7245f3..2ddaf87e1b 100644
> --- a/tools/qt-faststart.c
> +++ b/tools/qt-faststart.c
> @@ -96,9 +96,11 @@ int main(int argc, char *argv[])
> int64_t last_offset;
> unsigned char *moov_atom = NULL;
> unsigned char *ftyp_atom = NULL;
> + unsigned char *ptr;
> + unsigned char *end;
> uint64_t moov_atom_size;
> uint64_t ftyp_atom_size = 0;
> - uint64_t i, j;
> + uint64_t i;
> uint32_t offset_count;
> uint64_t current_offset;
> int64_t start_offset = 0;
> @@ -253,13 +255,16 @@ int main(int argc, char *argv[])
> printf(" bad atom size/element count\n");
> goto error_out;
> }
> - for (j = 0; j < offset_count; j++) {
> - current_offset = BE_32(&moov_atom[i + 12 + j * 4]);
> +
> + ptr = moov_atom + i + 12;
> + end = ptr + offset_count * 4;
> + while (ptr < end) {
> + current_offset = BE_32(ptr);
> current_offset += moov_atom_size;
> - moov_atom[i + 12 + j * 4 + 0] = (current_offset >> 24) &
> 0xFF;
> - moov_atom[i + 12 + j * 4 + 1] = (current_offset >> 16) &
> 0xFF;
> - moov_atom[i + 12 + j * 4 + 2] = (current_offset >> 8) &
> 0xFF;
> - moov_atom[i + 12 + j * 4 + 3] = (current_offset >> 0) &
> 0xFF;
> + *ptr++ = (current_offset >> 24) & 0xFF;
> + *ptr++ = (current_offset >> 16) & 0xFF;
> + *ptr++ = (current_offset >> 8) & 0xFF;
> + *ptr++ = (current_offset >> 0) & 0xFF;
> }
> i += atom_size - 4;
> } else if (atom_type == CO64_ATOM) {
> @@ -274,17 +279,20 @@ int main(int argc, char *argv[])
> printf(" bad atom size/element count\n");
> goto error_out;
> }
> - for (j = 0; j < offset_count; j++) {
> - current_offset = BE_64(&moov_atom[i + 12 + j * 8]);
> +
> + ptr = moov_atom + i + 12;
> + end = ptr + offset_count * 8;
> + while (ptr < end) {
> + current_offset = BE_64(ptr);
> current_offset += moov_atom_size;
> - moov_atom[i + 12 + j * 8 + 0] = (current_offset >> 56) &
> 0xFF;
> - moov_atom[i + 12 + j * 8 + 1] = (current_offset >> 48) &
> 0xFF;
> - moov_atom[i + 12 + j * 8 + 2] = (current_offset >> 40) &
> 0xFF;
> - moov_atom[i + 12 + j * 8 + 3] = (current_offset >> 32) &
> 0xFF;
> - moov_atom[i + 12 + j * 8 + 4] = (current_offset >> 24) &
> 0xFF;
> - moov_atom[i + 12 + j * 8 + 5] = (current_offset >> 16) &
> 0xFF;
> - moov_atom[i + 12 + j * 8 + 6] = (current_offset >> 8) &
> 0xFF;
> - moov_atom[i + 12 + j * 8 + 7] = (current_offset >> 0) &
> 0xFF;
> + *ptr++ = (current_offset >> 56) & 0xFF;
> + *ptr++ = (current_offset >> 48) & 0xFF;
> + *ptr++ = (current_offset >> 40) & 0xFF;
> + *ptr++ = (current_offset >> 32) & 0xFF;
> + *ptr++ = (current_offset >> 24) & 0xFF;
> + *ptr++ = (current_offset >> 16) & 0xFF;
> + *ptr++ = (current_offset >> 8) & 0xFF;
> + *ptr++ = (current_offset >> 0) & 0xFF;
can this be simplfified with
libavcodec/bytestream.h, libavutil/intreadwrite.h
or similar ?
[...]
--
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