avcodec/mjpegenc_common: Move stuff only used by mjpegenc.c to it

This allows to make ff_init_uni_ac_vlc static;
ff_mjpeg_encode_picture_frame has also been made static, but it could
always have been made static.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>

1 files changed, 189 insertions, 2 deletions

diff --git a/libavcodec/mjpegenc.c b/libavcodec/mjpegenc.c
index 466f48eba9..22af094da7 100644
--- a/libavcodec/mjpegenc.c
+++ b/libavcodec/mjpegenc.c
@@ -35,11 +35,198 @@
 #include "avcodec.h"
 #include "jpegtables.h"
 #include "mjpegenc_common.h"
+#include "mjpegenc_huffman.h"
 #include "mpegvideo.h"
 #include "mjpeg.h"
 #include "mjpegenc.h"
 #include "profiles.h"
 
+static av_cold void init_uni_ac_vlc(const uint8_t huff_size_ac[256],
+                                    uint8_t *uni_ac_vlc_len)
+{
+    for (int i = 0; i < 128; i++) {
+        int level = i - 64;
+        if (!level)
+            continue;
+        for (int run = 0; run < 64; run++) {
+            int len, code, nbits;
+            int alevel = FFABS(level);
+
+            len = (run >> 4) * huff_size_ac[0xf0];
+
+            nbits= av_log2_16bit(alevel) + 1;
+            code = ((15&run) << 4) | nbits;
+
+            len += huff_size_ac[code] + nbits;
+
+            uni_ac_vlc_len[UNI_AC_ENC_INDEX(run, i)] = len;
+            // We ignore EOB as its just a constant which does not change generally
+        }
+    }
+}
+
+/**
+ * Encodes and outputs the entire frame in the JPEG format.
+ *
+ * @param s The MpegEncContext.
+ */
+static void mjpeg_encode_picture_frame(MpegEncContext *s)
+{
+    int nbits, code, table_id;
+    MJpegContext *m = s->mjpeg_ctx;
+    uint8_t  *huff_size[4] = { m->huff_size_dc_luminance,
+                               m->huff_size_dc_chrominance,
+                               m->huff_size_ac_luminance,
+                               m->huff_size_ac_chrominance };
+    uint16_t *huff_code[4] = { m->huff_code_dc_luminance,
+                               m->huff_code_dc_chrominance,
+                               m->huff_code_ac_luminance,
+                               m->huff_code_ac_chrominance };
+    size_t total_bits = 0;
+    size_t bytes_needed;
+
+    s->header_bits = get_bits_diff(s);
+    // Estimate the total size first
+    for (int i = 0; i < m->huff_ncode; i++) {
+        table_id = m->huff_buffer[i].table_id;
+        code = m->huff_buffer[i].code;
+        nbits = code & 0xf;
+
+        total_bits += huff_size[table_id][code] + nbits;
+    }
+
+    bytes_needed = (total_bits + 7) / 8;
+    ff_mpv_reallocate_putbitbuffer(s, bytes_needed, bytes_needed);
+
+    for (int i = 0; i < m->huff_ncode; i++) {
+        table_id = m->huff_buffer[i].table_id;
+        code = m->huff_buffer[i].code;
+        nbits = code & 0xf;
+
+        put_bits(&s->pb, huff_size[table_id][code], huff_code[table_id][code]);
+        if (nbits != 0) {
+            put_sbits(&s->pb, nbits, m->huff_buffer[i].mant);
+        }
+    }
+
+    m->huff_ncode = 0;
+    s->i_tex_bits = get_bits_diff(s);
+}
+
+/**
+ * Builds all 4 optimal Huffman tables.
+ *
+ * Uses the data stored in the JPEG buffer to compute the tables.
+ * Stores the Huffman tables in the bits_* and val_* arrays in the MJpegContext.
+ *
+ * @param m MJpegContext containing the JPEG buffer.
+ */
+static void mjpeg_build_optimal_huffman(MJpegContext *m)
+{
+    MJpegEncHuffmanContext dc_luminance_ctx;
+    MJpegEncHuffmanContext dc_chrominance_ctx;
+    MJpegEncHuffmanContext ac_luminance_ctx;
+    MJpegEncHuffmanContext ac_chrominance_ctx;
+    MJpegEncHuffmanContext *ctx[4] = { &dc_luminance_ctx,
+                                       &dc_chrominance_ctx,
+                                       &ac_luminance_ctx,
+                                       &ac_chrominance_ctx };
+    for (int i = 0; i < 4; i++)
+        ff_mjpeg_encode_huffman_init(ctx[i]);
+
+    for (int i = 0; i < m->huff_ncode; i++) {
+        int table_id = m->huff_buffer[i].table_id;
+        int code     = m->huff_buffer[i].code;
+
+        ff_mjpeg_encode_huffman_increment(ctx[table_id], code);
+    }
+
+    ff_mjpeg_encode_huffman_close(&dc_luminance_ctx,
+                                  m->bits_dc_luminance,
+                                  m->val_dc_luminance, 12);
+    ff_mjpeg_encode_huffman_close(&dc_chrominance_ctx,
+                                  m->bits_dc_chrominance,
+                                  m->val_dc_chrominance, 12);
+    ff_mjpeg_encode_huffman_close(&ac_luminance_ctx,
+                                  m->bits_ac_luminance,
+                                  m->val_ac_luminance, 256);
+    ff_mjpeg_encode_huffman_close(&ac_chrominance_ctx,
+                                  m->bits_ac_chrominance,
+                                  m->val_ac_chrominance, 256);
+
+    ff_mjpeg_build_huffman_codes(m->huff_size_dc_luminance,
+                                 m->huff_code_dc_luminance,
+                                 m->bits_dc_luminance,
+                                 m->val_dc_luminance);
+    ff_mjpeg_build_huffman_codes(m->huff_size_dc_chrominance,
+                                 m->huff_code_dc_chrominance,
+                                 m->bits_dc_chrominance,
+                                 m->val_dc_chrominance);
+    ff_mjpeg_build_huffman_codes(m->huff_size_ac_luminance,
+                                 m->huff_code_ac_luminance,
+                                 m->bits_ac_luminance,
+                                 m->val_ac_luminance);
+    ff_mjpeg_build_huffman_codes(m->huff_size_ac_chrominance,
+                                 m->huff_code_ac_chrominance,
+                                 m->bits_ac_chrominance,
+                                 m->val_ac_chrominance);
+}
+
+/**
+ * Writes the complete JPEG frame when optimal huffman tables are enabled,
+ * otherwise writes the stuffing.
+ *
+ * Header + values + stuffing.
+ *
+ * @param s The MpegEncContext.
+ * @return int Error code, 0 if successful.
+ */
+int ff_mjpeg_encode_stuffing(MpegEncContext *s)
+{
+    PutBitContext *pbc = &s->pb;
+    int mb_y = s->mb_y - !s->mb_x;
+    int ret;
+    MJpegContext *m;
+
+    m = s->mjpeg_ctx;
+
+    if (s->huffman == HUFFMAN_TABLE_OPTIMAL) {
+        mjpeg_build_optimal_huffman(m);
+
+        // Replace the VLCs with the optimal ones.
+        // The default ones may be used for trellis during quantization.
+        init_uni_ac_vlc(m->huff_size_ac_luminance,   m->uni_ac_vlc_len);
+        init_uni_ac_vlc(m->huff_size_ac_chrominance, m->uni_chroma_ac_vlc_len);
+        s->intra_ac_vlc_length      =
+        s->intra_ac_vlc_last_length = m->uni_ac_vlc_len;
+        s->intra_chroma_ac_vlc_length      =
+        s->intra_chroma_ac_vlc_last_length = m->uni_chroma_ac_vlc_len;
+
+        ff_mjpeg_encode_picture_header(s->avctx, &s->pb, &s->intra_scantable,
+                                       s->pred, s->intra_matrix, s->chroma_intra_matrix);
+        mjpeg_encode_picture_frame(s);
+    }
+
+    ret = ff_mpv_reallocate_putbitbuffer(s, put_bits_count(&s->pb) / 8 + 100,
+                                            put_bits_count(&s->pb) / 4 + 1000);
+    if (ret < 0) {
+        av_log(s->avctx, AV_LOG_ERROR, "Buffer reallocation failed\n");
+        goto fail;
+    }
+
+    ff_mjpeg_escape_FF(pbc, s->esc_pos);
+
+    if ((s->avctx->active_thread_type & FF_THREAD_SLICE) && mb_y < s->mb_height - 1)
+        put_marker(pbc, RST0 + (mb_y&7));
+    s->esc_pos = put_bits_count(pbc) >> 3;
+
+fail:
+    for (int i = 0; i < 3; i++)
+        s->last_dc[i] = 128 << s->intra_dc_precision;
+
+    return ret;
+}
+
 static int alloc_huffman(MpegEncContext *s)
 {
     MJpegContext *m = s->mjpeg_ctx;
@@ -106,8 +293,8 @@ av_cold int ff_mjpeg_encode_init(MpegEncContext *s)
                                  avpriv_mjpeg_bits_ac_chrominance,
                                  avpriv_mjpeg_val_ac_chrominance);
 
-    ff_init_uni_ac_vlc(m->huff_size_ac_luminance,   m->uni_ac_vlc_len);
-    ff_init_uni_ac_vlc(m->huff_size_ac_chrominance, m->uni_chroma_ac_vlc_len);
+    init_uni_ac_vlc(m->huff_size_ac_luminance,   m->uni_ac_vlc_len);
+    init_uni_ac_vlc(m->huff_size_ac_chrominance, m->uni_chroma_ac_vlc_len);
     s->intra_ac_vlc_length      =
     s->intra_ac_vlc_last_length = m->uni_ac_vlc_len;
     s->intra_chroma_ac_vlc_length      =