diff options
| -rw-r--r-- | tools/info.c | 51 |
1 files changed, 50 insertions, 1 deletions
diff --git a/tools/info.c b/tools/info.c index 03da252..440939f 100644 --- a/tools/info.c +++ b/tools/info.c @@ -110,6 +110,49 @@ detect_webp(const uint8_t *p, size_t len) } static jv +parse_webp_vp8(jv o, const uint8_t *p, size_t len) +{ + if (len < 10 || (p[0] & 1) != 0 /* key frame */ || + p[3] != 0x9d || p[4] != 0x01 || p[5] != 0x2a) { + return add_warning(o, "invalid VP8 chunk"); + } + + o = jv_set(o, jv_string("width"), jv_number(u16le(p + 6) & 0x3fff)); + o = jv_set(o, jv_string("height"), jv_number(u16le(p + 8) & 0x3fff)); + return o; +} + +static jv +parse_webp_vp8l(jv o, const uint8_t *p, size_t len) +{ + if (len < 5 || p[0] != 0x2f) + return add_warning(o, "invalid VP8L chunk"); + + // Reading LSB-first from a little endian value means reading in order. + uint32_t header = u32le(p + 1); + o = jv_set(o, jv_string("width"), jv_number((header & 0x3fff) + 1)); + header >>= 14; + o = jv_set(o, jv_string("height"), jv_number((header & 0x3fff) + 1)); + header >>= 14; + o = jv_set(o, jv_string("alpha_is_used"), jv_bool(header & 1)); + return o; +} + +static jv +parse_webp_vp8x(jv o, const uint8_t *p, size_t len) +{ + if (len < 10) + return add_warning(o, "invalid VP8X chunk"); + + // Most of the fields in this chunk are duplicate or inferrable. + // Probably not worth decoding or verifying. + // TODO(p): For animations, we need to use the width and height from here. + uint8_t flags = p[0]; + o = jv_set(o, jv_string("animation"), jv_bool((flags >> 1) & 1)); + return o; +} + +static jv parse_webp(jv o, const uint8_t *p, size_t len) { if (!detect_webp(p, len)) @@ -144,7 +187,13 @@ parse_webp(jv o, const uint8_t *p, size_t len) chunks = jv_array_append(chunks, jv_string(fourcc)); p += 8; - // TODO(p): Decode VP8 and VP8L chunk metadata. + // TODO(p): Decode more chunks. + if (!strcmp(fourcc, "VP8 ")) + o = parse_webp_vp8(o, p, chunk_size); + if (!strcmp(fourcc, "VP8L")) + o = parse_webp_vp8l(o, p, chunk_size); + if (!strcmp(fourcc, "VP8X")) + o = parse_webp_vp8x(o, p, chunk_size); if (!strcmp(fourcc, "EXIF")) o = parse_exif(o, p, chunk_size); if (!strcmp(fourcc, "ICCP")) |