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avformat/matroskaenc: Improve writing Projection

The Matroska Projection master element has such a small maximum length
that it can always be written with a length field of length one.
So it is unnecessary to first write the element into a dynamic buffer to
get the accurate length in order not to waste bytes on the length field.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>
This commit is contained in:
Andreas Rheinhardt 2020-01-01 01:58:19 +01:00 committed by James Almer
parent 8867efa85f
commit 9c8aa86883

View File

@ -945,10 +945,8 @@ static int mkv_write_video_projection(AVFormatContext *s, AVIOContext *pb,
AVStream *st)
{
AVIOContext b;
AVIOContext *dyn_cp;
ebml_master projection;
int side_data_size = 0;
int ret, projection_size;
uint8_t *projection_ptr;
uint8_t private[20];
const AVSphericalMapping *spherical =
@ -958,62 +956,60 @@ static int mkv_write_video_projection(AVFormatContext *s, AVIOContext *pb,
if (!side_data_size)
return 0;
ret = avio_open_dyn_buf(&dyn_cp);
if (ret < 0)
return ret;
if (spherical->projection != AV_SPHERICAL_EQUIRECTANGULAR &&
spherical->projection != AV_SPHERICAL_EQUIRECTANGULAR_TILE &&
spherical->projection != AV_SPHERICAL_CUBEMAP) {
av_log(s, AV_LOG_WARNING, "Unknown projection type\n");
return 0;
}
// Maximally 4 8-byte elements with id-length 2 + 1 byte length field
// and the private data of the AV_SPHERICAL_EQUIRECTANGULAR_TILE case
projection = start_ebml_master(pb, MATROSKA_ID_VIDEOPROJECTION,
4 * (2 + 1 + 8) + (2 + 1 + 20));
switch (spherical->projection) {
case AV_SPHERICAL_EQUIRECTANGULAR:
put_ebml_uint(dyn_cp, MATROSKA_ID_VIDEOPROJECTIONTYPE,
put_ebml_uint(pb, MATROSKA_ID_VIDEOPROJECTIONTYPE,
MATROSKA_VIDEO_PROJECTION_TYPE_EQUIRECTANGULAR);
break;
case AV_SPHERICAL_EQUIRECTANGULAR_TILE:
ffio_init_context(&b, private, 20, 1, NULL, NULL, NULL, NULL);
put_ebml_uint(dyn_cp, MATROSKA_ID_VIDEOPROJECTIONTYPE,
put_ebml_uint(pb, MATROSKA_ID_VIDEOPROJECTIONTYPE,
MATROSKA_VIDEO_PROJECTION_TYPE_EQUIRECTANGULAR);
avio_wb32(&b, 0); // version + flags
avio_wb32(&b, spherical->bound_top);
avio_wb32(&b, spherical->bound_bottom);
avio_wb32(&b, spherical->bound_left);
avio_wb32(&b, spherical->bound_right);
put_ebml_binary(dyn_cp, MATROSKA_ID_VIDEOPROJECTIONPRIVATE,
put_ebml_binary(pb, MATROSKA_ID_VIDEOPROJECTIONPRIVATE,
private, avio_tell(&b));
break;
case AV_SPHERICAL_CUBEMAP:
ffio_init_context(&b, private, 12, 1, NULL, NULL, NULL, NULL);
put_ebml_uint(dyn_cp, MATROSKA_ID_VIDEOPROJECTIONTYPE,
put_ebml_uint(pb, MATROSKA_ID_VIDEOPROJECTIONTYPE,
MATROSKA_VIDEO_PROJECTION_TYPE_CUBEMAP);
avio_wb32(&b, 0); // version + flags
avio_wb32(&b, 0); // layout
avio_wb32(&b, spherical->padding);
put_ebml_binary(dyn_cp, MATROSKA_ID_VIDEOPROJECTIONPRIVATE,
put_ebml_binary(pb, MATROSKA_ID_VIDEOPROJECTIONPRIVATE,
private, avio_tell(&b));
break;
default:
av_log(s, AV_LOG_WARNING, "Unknown projection type\n");
goto end;
av_assert0(0);
}
if (spherical->yaw)
put_ebml_float(dyn_cp, MATROSKA_ID_VIDEOPROJECTIONPOSEYAW,
put_ebml_float(pb, MATROSKA_ID_VIDEOPROJECTIONPOSEYAW,
(double) spherical->yaw / (1 << 16));
if (spherical->pitch)
put_ebml_float(dyn_cp, MATROSKA_ID_VIDEOPROJECTIONPOSEPITCH,
put_ebml_float(pb, MATROSKA_ID_VIDEOPROJECTIONPOSEPITCH,
(double) spherical->pitch / (1 << 16));
if (spherical->roll)
put_ebml_float(dyn_cp, MATROSKA_ID_VIDEOPROJECTIONPOSEROLL,
put_ebml_float(pb, MATROSKA_ID_VIDEOPROJECTIONPOSEROLL,
(double) spherical->roll / (1 << 16));
end:
projection_size = avio_close_dyn_buf(dyn_cp, &projection_ptr);
if (projection_size) {
ebml_master projection = start_ebml_master(pb,
MATROSKA_ID_VIDEOPROJECTION,
projection_size);
avio_write(pb, projection_ptr, projection_size);
end_ebml_master(pb, projection);
}
av_freep(&projection_ptr);
return 0;
}