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swscale/utils: add SwsFormat abstraction and helpers

Groups together all relevant color metadata from an AVFrame. While we could use AVFrame directly, keeping it a separate struct has three advantages: 1. Functions accepting an SwsFormat will definitely not care about the data pointers. 2. It clearly separates sanitized and raw metadata, since the function to construct an SwsFormat from an AVFrame will also sanitize. 3. It's slightly more lightweight to pass around. Move these into a new header file "utils.h" to avoid crowding swscale_internal.h even more, and also to solve a circular dependency issue down the line.

Niklas Haas committed 2 years ago

Commit e2637a01 parent 87baf9a2 files · +139 −0Browse files

Unified · Split

2 files
  1. libswscale/utils.c +64 −0
  2. libswscale/utils.h +75 −0
libswscale/utils.c+64−0
@@ -1,4 +1,5 @@
11 /*
2+ * Copyright (C) 2024 Niklas Haas
23 * Copyright (C) 2001-2003 Michael Niedermayer <michaelni@gmx.at>
34 *
45 * This file is part of FFmpeg.
@@ -59,6 +60,7 @@ · 54 unmodified lines
5960 #include "rgb2rgb.h"
6061 #include "swscale.h"
6162 #include "swscale_internal.h"
63+#include "utils.h"
6264
6365 typedef struct FormatEntry {
6466 uint8_t is_supported_in :1;
@@ -2645,3 +2647,65 @@ int ff_range_add(RangeList *rl, unsigned int start, unsigned int len) · 2580 unmodified lines
26452647
26462648 return 0;
26472649 }
2650+
2651+/**
2652+ * This function also sanitizes and strips the input data, removing irrelevant
2653+ * fields for certain formats.
2654+ */
2655+SwsFormat ff_fmt_from_frame(const AVFrame *frame, int field)
2656+{
2657+ const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(frame->format);
2658+ SwsFormat fmt = {
2659+ .width = frame->width,
2660+ .height = frame->height,
2661+ .format = frame->format,
2662+ .range = frame->color_range,
2663+ .prim = frame->color_primaries,
2664+ .trc = frame->color_trc,
2665+ .csp = frame->colorspace,
2666+ .loc = frame->chroma_location,
2667+ .desc = desc,
2668+ };
2669+
2670+ av_assert1(fmt.width > 0);
2671+ av_assert1(fmt.height > 0);
2672+ av_assert1(fmt.format != AV_PIX_FMT_NONE);
2673+ av_assert0(desc);
2674+ if (desc->flags & (AV_PIX_FMT_FLAG_RGB | AV_PIX_FMT_FLAG_PAL | AV_PIX_FMT_FLAG_BAYER)) {
2675+ /* RGB-like family */
2676+ fmt.csp = AVCOL_SPC_RGB;
2677+ fmt.range = AVCOL_RANGE_JPEG;
2678+ } else if (desc->flags & AV_PIX_FMT_FLAG_XYZ) {
2679+ fmt.csp = AVCOL_SPC_UNSPECIFIED;
2680+ fmt.prim = AVCOL_PRI_SMPTE428;
2681+ fmt.trc = AVCOL_TRC_SMPTE428;
2682+ } else if (desc->nb_components < 3) {
2683+ /* Grayscale formats */
2684+ fmt.prim = AVCOL_PRI_UNSPECIFIED;
2685+ fmt.csp = AVCOL_SPC_UNSPECIFIED;
2686+ if (desc->flags & AV_PIX_FMT_FLAG_FLOAT)
2687+ fmt.range = AVCOL_RANGE_UNSPECIFIED;
2688+ else
2689+ fmt.range = AVCOL_RANGE_JPEG; // FIXME: this restriction should be lifted
2690+ }
2691+
2692+ switch (frame->format) {
2693+ case AV_PIX_FMT_YUVJ420P:
2694+ case AV_PIX_FMT_YUVJ411P:
2695+ case AV_PIX_FMT_YUVJ422P:
2696+ case AV_PIX_FMT_YUVJ444P:
2697+ case AV_PIX_FMT_YUVJ440P:
2698+ fmt.range = AVCOL_RANGE_JPEG;
2699+ break;
2700+ }
2701+
2702+ if (!desc->log2_chroma_w && !desc->log2_chroma_h)
2703+ fmt.loc = AVCHROMA_LOC_UNSPECIFIED;
2704+
2705+ if (frame->flags & AV_FRAME_FLAG_INTERLACED) {
2706+ fmt.height = (fmt.height + (field == FIELD_TOP)) >> 1;
2707+ fmt.interlaced = 1;
2708+ }
2709+
2710+ return fmt;
2711+}
libswscale/utils.h+75−0
@@ -0,0 +1,75 @@
1+/*
2+ * Copyright (C) 2024 Niklas Haas
3+ *
4+ * This file is part of FFmpeg.
5+ *
6+ * FFmpeg is free software; you can redistribute it and/or
7+ * modify it under the terms of the GNU Lesser General Public
8+ * License as published by the Free Software Foundation; either
9+ * version 2.1 of the License, or (at your option) any later version.
10+ *
11+ * FFmpeg is distributed in the hope that it will be useful,
12+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
13+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14+ * Lesser General Public License for more details.
15+ *
16+ * You should have received a copy of the GNU Lesser General Public
17+ * License along with FFmpeg; if not, write to the Free Software
18+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19+ */
20+
21+#ifndef SWSCALE_UTILS_H
22+#define SWSCALE_UTILS_H
23+
24+#include "libavutil/pixdesc.h"
25+
26+#include "swscale.h"
27+
28+enum {
29+ FIELD_TOP, /* top/even rows, or progressive */
30+ FIELD_BOTTOM, /* bottom/odd rows */
31+};
32+
33+/* Subset of AVFrame parameters that uniquely determine pixel representation */
34+typedef struct SwsFormat {
35+ int width, height;
36+ int interlaced;
37+ enum AVPixelFormat format;
38+ enum AVColorRange range;
39+ enum AVColorPrimaries prim;
40+ enum AVColorTransferCharacteristic trc;
41+ enum AVColorSpace csp;
42+ enum AVChromaLocation loc;
43+ const AVPixFmtDescriptor *desc; /* convenience */
44+} SwsFormat;
45+
46+/**
47+ * This function also sanitizes and strips the input data, removing irrelevant
48+ * fields for certain formats.
49+ */
50+SwsFormat ff_fmt_from_frame(const AVFrame *frame, int field);
51+
52+static inline int ff_fmt_equal(const SwsFormat *fmt1, const SwsFormat *fmt2)
53+{
54+ return fmt1->width == fmt2->width &&
55+ fmt1->height == fmt2->height &&
56+ fmt1->interlaced == fmt2->interlaced &&
57+ fmt1->format == fmt2->format &&
58+ fmt1->range == fmt2->range &&
59+ fmt1->prim == fmt2->prim &&
60+ fmt1->trc == fmt2->trc &&
61+ fmt1->csp == fmt2->csp &&
62+ fmt1->loc == fmt2->loc;
63+}
64+
65+static inline int ff_fmt_align(enum AVPixelFormat fmt)
66+{
67+ const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(fmt);
68+ if (desc->flags & AV_PIX_FMT_FLAG_BAYER) {
69+ return 2;
70+ } else {
71+ return 1 << desc->log2_chroma_h;
72+ }
73+}
74+
75+#endif /* SWSCALE_UTILS_H */

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