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Add Alpha Decode support from WebPDecode.

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Extend WebP decode functionality to extract Alpha data (support ALPH
chunk) and decode the Alpha plane using Alpha (utils/alpha) core-lib.

Change-Id: I6f0ee1b189c13caba3c1dd9b681383bfd00aa212
This commit is contained in:
Vikas Arora
2011-12-01 08:57:36 +05:30
parent e1947a9299
commit d117a94046
8 changed files with 62 additions and 77 deletions
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15
src/dec/webpi.h
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@ -95,10 +95,13 @@ VP8StatusCode WebPParseVP8X(const uint8_t** data, uint32_t* data_size,
// VP8_STATUS_NOT_ENOUGH_DATA in case of insufficient data, and
// VP8_STATUS_OK otherwise.
// If a VP8 chunk is found, bytes_skipped is set to the total number of bytes
// that are skipped.
// that are skipped. Also, if an alpha chunk is found, alpha_data and alpha_size
// are set appropriately.
VP8StatusCode WebPParseOptionalChunks(const uint8_t** data, uint32_t* data_size,
uint32_t riff_size,
uint32_t* bytes_skipped);
uint32_t* bytes_skipped,
const uint8_t** alpha_data,
uint32_t* alpha_size);
// Validates the VP8 Header ("VP8 nnnn") and skips over it.
// Returns VP8_STATUS_BITSTREAM_ERROR for invalid (vp8_chunk_size greater than
@ -117,12 +120,14 @@ VP8StatusCode WebPParseVP8Header(const uint8_t** data, uint32_t* data_size,
// Returns VP8_STATUS_OK on success,
// VP8_STATUS_BITSTREAM_ERROR if an invalid header/chunk is found, and
// VP8_STATUS_NOT_ENOUGH_DATA if case of insufficient data.
// Also, data, data_size, vp8_size & bytes_skipped are updated appropriately
// on success, where
// Also, data, data_size, vp8_size, bytes_skipped, alpha_data & alpha_size are
// updated appropriately on success, where
// vp8_size is the size of VP8 chunk data (extracted from VP8 chunk header) and
// bytes_skipped is set to the total number of bytes that are skipped.
VP8StatusCode WebPParseHeaders(const uint8_t** data, uint32_t* data_size,
uint32_t* vp8_size, uint32_t* bytes_skipped);
uint32_t* vp8_size, uint32_t* bytes_skipped,
const uint8_t** alpha_data,
uint32_t* alpha_size);
//------------------------------------------------------------------------------
// Misc utils