| Line | Branch | Exec | Source |
|---|---|---|---|
| 1 | /* | ||
| 2 | * ASTC demuxer (.astc container) | ||
| 3 | * Copyright (c) 2026 Jun Zhao | ||
| 4 | * | ||
| 5 | * This file is part of FFmpeg. | ||
| 6 | * | ||
| 7 | * FFmpeg is free software; you can redistribute it and/or | ||
| 8 | * modify it under the terms of the GNU Lesser General Public | ||
| 9 | * License as published by the Free Software Foundation; either | ||
| 10 | * version 2.1 of the License, or (at your option) any later version. | ||
| 11 | * | ||
| 12 | * FFmpeg is distributed in the hope that it will be useful, | ||
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | ||
| 15 | * Lesser General Public License for more details. | ||
| 16 | * | ||
| 17 | * You should have received a copy of the GNU Lesser General Public | ||
| 18 | * License along with FFmpeg; if not, write to the Free Software | ||
| 19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | ||
| 20 | */ | ||
| 21 | |||
| 22 | /** | ||
| 23 | * @file | ||
| 24 | * ASTC (Adaptive Scalable Texture Compression) demuxer. | ||
| 25 | * | ||
| 26 | * Reads the 16-byte .astc header, exposes it as extradata to the decoder, | ||
| 27 | * and emits the raw ASTC bitstream as a single packet. | ||
| 28 | */ | ||
| 29 | |||
| 30 | #include "config_components.h" | ||
| 31 | |||
| 32 | #include <inttypes.h> | ||
| 33 | #include <limits.h> | ||
| 34 | |||
| 35 | #include "avformat.h" | ||
| 36 | #include "avio.h" | ||
| 37 | #include "avio_internal.h" | ||
| 38 | #include "demux.h" | ||
| 39 | #include "internal.h" | ||
| 40 | #include "libavutil/intreadwrite.h" | ||
| 41 | |||
| 42 | #define ASTC_HEADER_SIZE 16 | ||
| 43 | #define ASTC_BLOCK_BYTES 16 | ||
| 44 | static const uint8_t astc_magic[4] = { 0x13, 0xAB, 0xA1, 0x5C }; | ||
| 45 | |||
| 46 | typedef struct ASTCDemuxerContext { | ||
| 47 | uint64_t image_size; | ||
| 48 | int truncated; | ||
| 49 | } ASTCDemuxerContext; | ||
| 50 | |||
| 51 | 8043 | static int astc_probe(const AVProbeData *p) | |
| 52 | { | ||
| 53 |
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8043 | if (p->buf_size >= ASTC_HEADER_SIZE && |
| 54 |
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8043 | !memcmp(p->buf, astc_magic, sizeof(astc_magic))) |
| 55 | ✗ | return AVPROBE_SCORE_MAX; | |
| 56 | 8043 | return 0; | |
| 57 | } | ||
| 58 | |||
| 59 | ✗ | static int astc_read_header(AVFormatContext *s) | |
| 60 | { | ||
| 61 | ✗ | AVIOContext *pb = s->pb; | |
| 62 | ✗ | ASTCDemuxerContext *astc = s->priv_data; | |
| 63 | AVStream *st; | ||
| 64 | uint8_t hdr[ASTC_HEADER_SIZE]; | ||
| 65 | unsigned int bx, by, bz, w, h, dz; | ||
| 66 | uint64_t expected; | ||
| 67 | |||
| 68 | ✗ | if (ffio_read_size(pb, hdr, ASTC_HEADER_SIZE) < 0) | |
| 69 | ✗ | return AVERROR_INVALIDDATA; | |
| 70 | |||
| 71 | ✗ | if (memcmp(hdr, astc_magic, sizeof(astc_magic))) { | |
| 72 | ✗ | av_log(s, AV_LOG_ERROR, "Not an ASTC file (bad magic).\n"); | |
| 73 | ✗ | return AVERROR_INVALIDDATA; | |
| 74 | } | ||
| 75 | |||
| 76 | ✗ | bx = hdr[4]; | |
| 77 | ✗ | by = hdr[5]; | |
| 78 | ✗ | bz = hdr[6]; | |
| 79 | ✗ | w = AV_RL24(hdr + 7); | |
| 80 | ✗ | h = AV_RL24(hdr + 10); | |
| 81 | ✗ | dz = AV_RL24(hdr + 13); | |
| 82 | |||
| 83 | /* Validate the geometry before trusting it to size the packet: the | ||
| 84 | * decoder only handles 2D images, and a zero block size would divide | ||
| 85 | * by zero when deriving the block count. */ | ||
| 86 | ✗ | if (!bx || !by || !bz || !w || !h || dz != 1) { | |
| 87 | ✗ | av_log(s, AV_LOG_ERROR, | |
| 88 | "Invalid ASTC header: block %ux%ux%u, image %ux%ux%u.\n", | ||
| 89 | bx, by, bz, w, h, dz); | ||
| 90 | ✗ | return AVERROR_INVALIDDATA; | |
| 91 | } | ||
| 92 | |||
| 93 | /* Multiply the block counts in 64 bits: the dimensions fit 24 bits, but | ||
| 94 | * their product overflows 32 bits for large images, and a wrapped result | ||
| 95 | * would under-size the packet, or wrap to zero and look like EOF. */ | ||
| 96 | ✗ | expected = (((uint64_t)w + bx - 1) / bx) * | |
| 97 | ✗ | (((uint64_t)h + by - 1) / by) * | |
| 98 | ✗ | (((uint64_t)dz + bz - 1) / bz) * ASTC_BLOCK_BYTES; | |
| 99 | ✗ | if (expected > INT_MAX) { | |
| 100 | ✗ | av_log(s, AV_LOG_ERROR, "ASTC image is too large (%"PRIu64" bytes).\n", | |
| 101 | expected); | ||
| 102 | ✗ | return AVERROR_INVALIDDATA; | |
| 103 | } | ||
| 104 | ✗ | astc->image_size = expected; | |
| 105 | |||
| 106 | ✗ | st = avformat_new_stream(s, NULL); | |
| 107 | ✗ | if (!st) | |
| 108 | ✗ | return AVERROR(ENOMEM); | |
| 109 | |||
| 110 | ✗ | st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO; | |
| 111 | ✗ | st->codecpar->codec_id = AV_CODEC_ID_ASTC; | |
| 112 | ✗ | st->codecpar->width = w; | |
| 113 | ✗ | st->codecpar->height = h; | |
| 114 | ✗ | st->codecpar->format = AV_PIX_FMT_RGBA; | |
| 115 | |||
| 116 | ✗ | if (ff_alloc_extradata(st->codecpar, ASTC_HEADER_SIZE) < 0) | |
| 117 | ✗ | return AVERROR(ENOMEM); | |
| 118 | ✗ | memcpy(st->codecpar->extradata, hdr, ASTC_HEADER_SIZE); | |
| 119 | |||
| 120 | /* Single image container. */ | ||
| 121 | ✗ | st->duration = 1; | |
| 122 | ✗ | avpriv_set_pts_info(st, 64, 1, 1); | |
| 123 | |||
| 124 | ✗ | return 0; | |
| 125 | } | ||
| 126 | |||
| 127 | ✗ | static int astc_read_packet(AVFormatContext *s, AVPacket *pkt) | |
| 128 | { | ||
| 129 | ✗ | ASTCDemuxerContext *astc = s->priv_data; | |
| 130 | int ret; | ||
| 131 | |||
| 132 | /* Keep reporting a detected truncation instead of falling through to EOF: | ||
| 133 | * a caller that stops at the first error must not see the broken image as | ||
| 134 | * a clean end of stream. */ | ||
| 135 | ✗ | if (astc->truncated) | |
| 136 | ✗ | return AVERROR_INVALIDDATA; | |
| 137 | |||
| 138 | ✗ | if (!astc->image_size) | |
| 139 | ✗ | return AVERROR_EOF; | |
| 140 | |||
| 141 | /* Read exactly one image worth of blocks; a short read means the input | ||
| 142 | * is truncated, and any trailing data is not part of this image. A payload | ||
| 143 | * that is missing entirely reads as EOF, which has to be reported as the | ||
| 144 | * truncation it is rather than as the end of a valid stream. */ | ||
| 145 | ✗ | ret = av_get_packet(s->pb, pkt, astc->image_size); | |
| 146 | ✗ | if (ret == AVERROR_EOF) | |
| 147 | ✗ | ret = 0; | |
| 148 | ✗ | if (ret < 0) | |
| 149 | ✗ | return ret; | |
| 150 | ✗ | if (ret != astc->image_size) { | |
| 151 | ✗ | av_log(s, AV_LOG_ERROR, | |
| 152 | "Truncated ASTC image: got %d of %"PRIu64" bytes.\n", | ||
| 153 | ret, astc->image_size); | ||
| 154 | ✗ | av_packet_unref(pkt); | |
| 155 | ✗ | astc->truncated = 1; | |
| 156 | ✗ | return AVERROR_INVALIDDATA; | |
| 157 | } | ||
| 158 | |||
| 159 | ✗ | astc->image_size = 0; | |
| 160 | ✗ | pkt->stream_index = 0; | |
| 161 | ✗ | pkt->flags |= AV_PKT_FLAG_KEY; | |
| 162 | ✗ | return 0; | |
| 163 | } | ||
| 164 | |||
| 165 | const FFInputFormat ff_astc_demuxer = { | ||
| 166 | .p.name = "astc", | ||
| 167 | .p.long_name = NULL_IF_CONFIG_SMALL("ASTC (Adaptive Scalable Texture Compression)"), | ||
| 168 | .p.mime_type = "image/astc", | ||
| 169 | .p.extensions = "astc", | ||
| 170 | .p.flags = AVFMT_NOTIMESTAMPS, | ||
| 171 | .priv_data_size = sizeof(ASTCDemuxerContext), | ||
| 172 | .read_probe = astc_probe, | ||
| 173 | .read_header = astc_read_header, | ||
| 174 | .read_packet = astc_read_packet, | ||
| 175 | }; | ||
| 176 |