[FFmpeg-devel] [PATCH] lavu/stereo3d: change baseline and horizontal FOV to rationals
James Almer
jamrial at gmail.com
Sun Jun 23 00:30:30 EEST 2024
On 6/22/2024 6:26 PM, Lynne via ffmpeg-devel wrote:
> On 22/06/2024 22:19, James Almer wrote:
>> On 6/22/2024 5:11 PM, Lynne via ffmpeg-devel wrote:
>>> This avoids hardcoding any implementation-specific limitiations as
>>> part of the API, and allows for future expandability.
>>>
>>> This also allows API users to more conveniently convert the
>>> values into floats without hardcoding specific conversion constants.
>>>
>>> The draft implementation of this mechanism for the draft of
>>> AVTransport uses rationals for these particular fields.
>>>
>>> The API was committed 2 days ago, so changing these fields now
>>> is within the realms of acceptable.
>>> ---
>>> fftools/ffprobe.c | 4 ++--
>>> libavformat/dump.c | 9 +++++----
>>> libavformat/mov.c | 9 ++++++---
>>> libavutil/stereo3d.h | 8 ++++----
>>> tests/ref/fate/matroska-spherical-mono | 4 ++--
>>> tests/ref/fate/matroska-spherical-mono-remux | 8 ++++----
>>> tests/ref/fate/matroska-stereo_mode | 16 ++++++++--------
>>> tests/ref/fate/matroska-vp8-alpha-remux | 4 ++--
>>> tests/ref/fate/mov-spherical-mono | 4 ++--
>>> 9 files changed, 35 insertions(+), 31 deletions(-)
>>>
>>> diff --git a/fftools/ffprobe.c b/fftools/ffprobe.c
>>> index d7ba980ff9..2da928b7c3 100644
>>> --- a/fftools/ffprobe.c
>>> +++ b/fftools/ffprobe.c
>>> @@ -2546,9 +2546,9 @@ static void print_pkt_side_data(WriterContext *w,
>>> print_int("inverted", !!(stereo->flags &
>>> AV_STEREO3D_FLAG_INVERT));
>>> print_str("view", av_stereo3d_view_name(stereo->view));
>>> print_str("primary_eye",
>>> av_stereo3d_primary_eye_name(stereo->primary_eye));
>>> - print_int("baseline", stereo->baseline);
>>> + print_q("baseline", stereo->baseline, '/');
>>> print_q("horizontal_disparity_adjustment", stereo-
>>> >horizontal_disparity_adjustment, '/');
>>> - print_int("horizontal_field_of_view", stereo-
>>> >horizontal_field_of_view);
>>> + print_q("horizontal_field_of_view", stereo-
>>> >horizontal_field_of_view, '/');
>>> } else if (sd->type == AV_PKT_DATA_SPHERICAL) {
>>> const AVSphericalMapping *spherical =
>>> (AVSphericalMapping *)sd->data;
>>> print_str("projection",
>>> av_spherical_projection_name(spherical->projection));
>>> diff --git a/libavformat/dump.c b/libavformat/dump.c
>>> index 61a2c6a29f..ac7d3038ab 100644
>>> --- a/libavformat/dump.c
>>> +++ b/libavformat/dump.c
>>> @@ -262,13 +262,14 @@ static void dump_stereo3d(void *ctx, const
>>> AVPacketSideData *sd, int log_level)
>>> av_log(ctx, log_level, "%s, view: %s, primary eye: %s",
>>> av_stereo3d_type_name(stereo->type),
>>> av_stereo3d_view_name(stereo->view),
>>> av_stereo3d_primary_eye_name(stereo->primary_eye));
>>> - if (stereo->baseline)
>>> - av_log(ctx, log_level, ", baseline: %"PRIu32"", stereo-
>>> >baseline);
>>> + if (stereo->baseline.num && stereo->baseline.den)
>>> + av_log(ctx, log_level, ", baseline: %d/%d", stereo-
>>> >baseline.num, stereo->baseline.den);
>>> if (stereo->horizontal_disparity_adjustment.num && stereo-
>>> >horizontal_disparity_adjustment.den)
>>> av_log(ctx, log_level, ", horizontal_disparity_adjustment:
>>> %d/%d",
>>> stereo->horizontal_disparity_adjustment.num, stereo-
>>> >horizontal_disparity_adjustment.den);
>>> - if (stereo->horizontal_field_of_view)
>>> - av_log(ctx, log_level, ", horizontal_field_of_view:
>>> %"PRIu32"", stereo->horizontal_field_of_view);
>>> + if (stereo->horizontal_field_of_view.num && stereo-
>>> >horizontal_field_of_view.den)
>>> + av_log(ctx, log_level, ", horizontal_field_of_view: %d/%d",
>>> stereo->horizontal_field_of_view.num,
>>> + stereo->horizontal_field_of_view.den);
>>> if (stereo->flags & AV_STEREO3D_FLAG_INVERT)
>>> av_log(ctx, log_level, " (inverted)");
>>> diff --git a/libavformat/mov.c b/libavformat/mov.c
>>> index f08fec3fb6..64cd17e770 100644
>>> --- a/libavformat/mov.c
>>> +++ b/libavformat/mov.c
>>> @@ -6545,7 +6545,8 @@ static int mov_read_eyes(MOVContext *c,
>>> AVIOContext *pb, MOVAtom atom)
>>> MOVStreamContext *sc;
>>> int size, flags = 0;
>>> int64_t remaining;
>>> - uint32_t tag, baseline = 0;
>>> + uint32_t tag;
>>> + AVRational baseline = av_make_q(0, 0);
>>> enum AVStereo3DView view = AV_STEREO3D_VIEW_PACKED;
>>> enum AVStereo3DPrimaryEye primary_eye = AV_PRIMARY_EYE_NONE;
>>> AVRational horizontal_disparity_adjustment = { 0, 1 };
>>> @@ -6642,7 +6643,8 @@ static int mov_read_eyes(MOVContext *c,
>>> AVIOContext *pb, MOVAtom atom)
>>> avio_skip(pb, 1); // version
>>> avio_skip(pb, 3); // flags
>>> - baseline = avio_rb32(pb);
>>> + baseline.num = avio_rb32(pb);
>>> + baseline.den = 1000000; // micrometers
>>> break;
>>> }
>>> @@ -6782,7 +6784,8 @@ static int mov_read_hfov(MOVContext *c,
>>> AVIOContext *pb, MOVAtom atom)
>>> return AVERROR(ENOMEM);
>>> }
>>> - sc->stereo3d->horizontal_field_of_view = avio_rb32(pb);
>>> + sc->stereo3d->horizontal_field_of_view.num = avio_rb32(pb);
>>> + sc->stereo3d->horizontal_field_of_view.den = 1000; // thousands
>>> of a degree
>>> return 0;
>>> }
>>> diff --git a/libavutil/stereo3d.h b/libavutil/stereo3d.h
>>> index 00a5c3900e..097f6c9455 100644
>>> --- a/libavutil/stereo3d.h
>>> +++ b/libavutil/stereo3d.h
>>> @@ -213,9 +213,9 @@ typedef struct AVStereo3D {
>>> /**
>>> * The distance between the centres of the lenses of the camera
>>> system,
>>> - * in micrometers. Zero if unset.
>>> + * in meters. Zero if unset.
>>> */
>>> - uint32_t baseline;
>>> + AVRational baseline;
>>
>> This is not ok. No reason for distance be a soft float, or allow
>> negative values. In the case of the blin box, it's a 32bit unsigned
>> value, which will not fit in AVRational.
>
> Added an (int32_t) cast locally. This is also how
> horizontal_disparity_adjustment is handled, with a uint32_t converted
> into a rational.
No, that one is an int32_t as it can be negative (Ranges -1.0 to 1.0),
thus it works fine as AVRational. baseline does not, so it should stay
an uint32_t.
>
>>
>> You can easily convert this in your code by using a 1000000
>> denominator if you wish.
>>
>>> /**
>>> * Relative shift of the left and right images, which changes
>>> the zero parallax plane.
>>> @@ -224,9 +224,9 @@ typedef struct AVStereo3D {
>>> AVRational horizontal_disparity_adjustment;
>>> /**
>>> - * Horizontal field of view in thousanths of a degree. Zero if
>>> unset.
>>> + * Horizontal field of view, in degrees. Zero if unset.
>>> */
>>> - uint32_t horizontal_field_of_view;
>>> + AVRational horizontal_field_of_view;
>>
>> This one i can't say. Would for example Matroska implement degrees as
>> a float, or uint?
>
> Likely a float (EBML_FLOAT). This is how mastering metadata and video
> projection are handled.
But Mastering metadata is not in degrees.
Wait for Derek to comment. He knows this field better than me.
>
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