Implement optimal huffman encoding for (M)JPEG.

> seems to break
> make fate-vsynth1-mjpeg-444

Fixed.

1 files changed, 59 insertions, 9 deletions

diff --git a/libavcodec/mjpegenc.h b/libavcodec/mjpegenc.h
index 60cd56677f..577fa1fec6 100644
--- a/libavcodec/mjpegenc.h
+++ b/libavcodec/mjpegenc.h
@@ -39,18 +39,67 @@
 #include "mpegvideo.h"
 #include "put_bits.h"
 
+/**
+ * Buffer of JPEG frame data.
+ *
+ * Optimal Huffman table generation requires the frame data to be loaded into
+ * a buffer so that the tables can be computed.
+ * There are at most mb_width*mb_height*12*64 of these per frame.
+ */
+typedef struct MJpegHuffmanCode {
+    // 0=DC lum, 1=DC chrom, 2=AC lum, 3=AC chrom
+    uint8_t table_id; ///< The Huffman table id associated with the data.
+    uint8_t code;     ///< The exponent.
+    uint16_t mant;    ///< The mantissa.
+} MJpegHuffmanCode;
+
+/**
+ * Holds JPEG frame data and Huffman table data.
+ */
 typedef struct MJpegContext {
-    uint8_t huff_size_dc_luminance[12]; //FIXME use array [3] instead of lumi / chroma, for easier addressing
-    uint16_t huff_code_dc_luminance[12];
-    uint8_t huff_size_dc_chrominance[12];
-    uint16_t huff_code_dc_chrominance[12];
+    //FIXME use array [3] instead of lumi / chroma, for easier addressing
+    uint8_t huff_size_dc_luminance[12];     ///< DC luminance Huffman table size.
+    uint16_t huff_code_dc_luminance[12];    ///< DC luminance Huffman table codes.
+    uint8_t huff_size_dc_chrominance[12];   ///< DC chrominance Huffman table size.
+    uint16_t huff_code_dc_chrominance[12];  ///< DC chrominance Huffman table codes.
+
+    uint8_t huff_size_ac_luminance[256];    ///< AC luminance Huffman table size.
+    uint16_t huff_code_ac_luminance[256];   ///< AC luminance Huffman table codes.
+    uint8_t huff_size_ac_chrominance[256];  ///< AC chrominance Huffman table size.
+    uint16_t huff_code_ac_chrominance[256]; ///< AC chrominance Huffman table codes.
 
-    uint8_t huff_size_ac_luminance[256];
-    uint16_t huff_code_ac_luminance[256];
-    uint8_t huff_size_ac_chrominance[256];
-    uint16_t huff_code_ac_chrominance[256];
+    /** Storage for AC luminance VLC (in MpegEncContext) */
+    uint8_t uni_ac_vlc_len[64 * 64 * 2];
+    /** Storage for AC chrominance VLC (in MpegEncContext) */
+    uint8_t uni_chroma_ac_vlc_len[64 * 64 * 2];
+
+    // Default DC tables have exactly 12 values
+    uint8_t bits_dc_luminance[17];   ///< DC luminance Huffman bits.
+    uint8_t val_dc_luminance[12];    ///< DC luminance Huffman values.
+    uint8_t bits_dc_chrominance[17]; ///< DC chrominance Huffman bits.
+    uint8_t val_dc_chrominance[12];  ///< DC chrominance Huffman values.
+
+    // 8-bit JPEG has max 256 values
+    uint8_t bits_ac_luminance[17];   ///< AC luminance Huffman bits.
+    uint8_t val_ac_luminance[256];   ///< AC luminance Huffman values.
+    uint8_t bits_ac_chrominance[17]; ///< AC chrominance Huffman bits.
+    uint8_t val_ac_chrominance[256]; ///< AC chrominance Huffman values.
+
+    unsigned int huff_capacity;      ///< Size of the buffer, in entries.
+    size_t huff_ncode;               ///< Number of current entries in the buffer.
+    MJpegHuffmanCode *huff_buffer;   ///< Buffer for Huffman code values.
+    int error;                       ///< Error code.
 } MJpegContext;
 
+/**
+ * Enum for the Huffman encoding strategy.
+ */
+enum HuffmanTableOption {
+    HUFFMAN_TABLE_DEFAULT = 0, ///< Use the default Huffman tables.
+    HUFFMAN_TABLE_OPTIMAL = 1, ///< Compute and use optimal Huffman tables.
+    NB_HUFFMAN_TABLE_OPTION = 2
+};
+
 static inline void put_marker(PutBitContext *p, enum JpegMarker code)
 {
     put_bits(p, 8, 0xff);
@@ -58,7 +107,8 @@ static inline void put_marker(PutBitContext *p, enum JpegMarker code)
 }
 
 int  ff_mjpeg_encode_init(MpegEncContext *s);
+void ff_mjpeg_encode_picture_frame(MpegEncContext *s);
 void ff_mjpeg_encode_close(MpegEncContext *s);
-void ff_mjpeg_encode_mb(MpegEncContext *s, int16_t block[12][64]);
+int ff_mjpeg_encode_mb(MpegEncContext *s, int16_t block[12][64]);
 
 #endif /* AVCODEC_MJPEGENC_H */