Minor comment fixes for the mini box code

Change bit(2) version; to bit(2) version = 0; to match the spec exactly.
wantehchang · Aug 15, 2024 · 4f1acb6 · 4f1acb6
1 parent 0d3e5e2
commit 4f1acb6
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Showing 3 changed files with 7 additions and 5 deletions.
diff --git a/include/avif/internal.h b/include/avif/internal.h
@@ -692,7 +692,7 @@ AVIF_NODISCARD avifBool avifROStreamReadBoxHeader(avifROStream * stream, avifBox
 AVIF_NODISCARD avifBool avifROStreamReadBoxHeaderPartial(avifROStream * stream, avifBoxHeader * header, avifBool topLevel); // This doesn't require that the full box can fit in the stream
 AVIF_NODISCARD avifBool avifROStreamReadVersionAndFlags(avifROStream * stream, uint8_t * version, uint32_t * flags); // version and flags ptrs are both optional
 AVIF_NODISCARD avifBool avifROStreamReadAndEnforceVersion(avifROStream * stream, uint8_t enforcedVersion); // currently discards flags
-// The following functions can write non-aligned bits.
+// The following functions can read non-aligned bits.
 AVIF_NODISCARD avifBool avifROStreamReadBits8(avifROStream * stream, uint8_t * v, size_t bitCount);
 AVIF_NODISCARD avifBool avifROStreamReadBits(avifROStream * stream, uint32_t * v, size_t bitCount);
 

diff --git a/src/read.c b/src/read.c
@@ -3572,7 +3572,7 @@ static avifResult avifParseMinimizedImageBox(avifMeta * meta, uint64_t rawOffset
     meta->fromMiniBox = AVIF_TRUE;
 
     uint32_t version;
-    AVIF_CHECKERR(avifROStreamReadBits(&s, &version, 2), AVIF_RESULT_BMFF_PARSE_FAILED); // bit(2) version;
+    AVIF_CHECKERR(avifROStreamReadBits(&s, &version, 2), AVIF_RESULT_BMFF_PARSE_FAILED); // bit(2) version = 0;
     AVIF_CHECKERR(version == 0, AVIF_RESULT_BMFF_PARSE_FAILED);
 
     // flags
@@ -3818,13 +3818,15 @@ static avifResult avifParseMinimizedImageBox(avifMeta * meta, uint64_t rawOffset
     // Chunks
     avifCodecConfigurationBox alphaItemCodecConfig = { 0 };
     if (hasAlpha && alphaItemDataSize != 0 && alphaItemCodecConfigSize != 0) {
+        // 'av1C' always uses 4 bytes.
         AVIF_CHECKERR(alphaItemCodecConfigSize == 4, AVIF_RESULT_BMFF_PARSE_FAILED);
         AVIF_CHECKERR(avifParseCodecConfiguration(&s, &alphaItemCodecConfig, (const char *)codecConfigType, diag),
                       AVIF_RESULT_BMFF_PARSE_FAILED); // unsigned int(8) alpha_item_codec_config[alpha_item_codec_config_size];
     }
     // if (hdr_flag && gainmap_flag && gainmap_item_codec_config_size > 0)
     //     unsigned int(8) gainmap_item_codec_config[gainmap_item_codec_config_size];
     avifCodecConfigurationBox mainItemCodecConfig = { 0 };
+    // 'av1C' always uses 4 bytes.
     AVIF_CHECKERR(mainItemCodecConfigSize == 4, AVIF_RESULT_BMFF_PARSE_FAILED);
     AVIF_CHECKERR(avifParseCodecConfiguration(&s, &mainItemCodecConfig, (const char *)codecConfigType, diag),
                   AVIF_RESULT_BMFF_PARSE_FAILED); // unsigned int(8) main_item_codec_config[main_item_codec_config_size];

diff --git a/src/write.c b/src/write.c
@@ -2462,14 +2462,14 @@ static avifResult avifEncoderWriteMiniBox(avifEncoder * encoder, avifRWStream *
     const avifBool hasExplicitCodecTypes = AVIF_FALSE; // 'av01' and 'av1C' known from 'avif' minor_version field of FileTypeBox.
 
     const uint32_t smallDimensionsFlag = image->width <= (1 << 7) && image->height <= (1 << 7);
-    const uint32_t codecConfigSize = 4;                                  // 'av1C' always uses 4 bytes.
-    const uint32_t fewCodecConfigBytesFlag = codecConfigSize < (1 << 3); // 'av1C' always uses 4 bytes.
+    const uint32_t codecConfigSize = 4; // 'av1C' always uses 4 bytes.
+    const uint32_t fewCodecConfigBytesFlag = codecConfigSize < (1 << 3);
     const uint32_t fewItemDataBytesFlag = colorData->size <= (1 << 15) && (!alphaData || alphaData->size < (1 << 15));
     const uint32_t fewMetadataBytesFlag = image->icc.size <= (1 << 10) && image->exif.size <= (1 << 10) && image->xmp.size <= (1 << 10);
 
     avifBoxMarker mini;
     AVIF_CHECKRES(avifRWStreamWriteBox(s, "mini", AVIF_BOX_SIZE_TBD, &mini));
-    AVIF_CHECKRES(avifRWStreamWriteBits(s, 0, 2)); // bit(2) version;
+    AVIF_CHECKRES(avifRWStreamWriteBits(s, 0, 2)); // bit(2) version = 0;
 
     // flags
     AVIF_CHECKRES(avifRWStreamWriteBits(s, hasExplicitCodecTypes, 1));    // bit(1) explicit_codec_types_flag;