av_cold int ff_mjpeg_encode_init(MpegEncContext *s) { MJpegContext *m; av_assert0(s->slice_context_count == 1); if (s->width > 65500 || s->height > 65500) { av_log(s, AV_LOG_ERROR, "JPEG does not support resolutions above 65500x65500\n"); return AVERROR(EINVAL); } m = av_malloc(sizeof(MJpegContext)); if (!m) return AVERROR(ENOMEM); s->min_qcoeff=-1023; s->max_qcoeff= 1023; // Build default Huffman tables. // These may be overwritten later with more optimal Huffman tables, but // they are needed at least right now for some processes like trellis. ff_mjpeg_build_huffman_codes(m->huff_size_dc_luminance, m->huff_code_dc_luminance, avpriv_mjpeg_bits_dc_luminance, avpriv_mjpeg_val_dc); ff_mjpeg_build_huffman_codes(m->huff_size_dc_chrominance, m->huff_code_dc_chrominance, avpriv_mjpeg_bits_dc_chrominance, avpriv_mjpeg_val_dc); ff_mjpeg_build_huffman_codes(m->huff_size_ac_luminance, m->huff_code_ac_luminance, avpriv_mjpeg_bits_ac_luminance, avpriv_mjpeg_val_ac_luminance); ff_mjpeg_build_huffman_codes(m->huff_size_ac_chrominance, m->huff_code_ac_chrominance, 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); 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; // Buffers start out empty. m->huff_ncode = 0; s->mjpeg_ctx = m; return alloc_huffman(s); }