void ff_mjpeg_encode_picture_header(AVCodecContext *avctx, PutBitContext *pb, ScanTable *intra_scantable, uint16_t intra_matrix[64]) { int chroma_h_shift, chroma_v_shift; const int lossless = avctx->codec_id != AV_CODEC_ID_MJPEG; int hsample[3], vsample[3]; av_pix_fmt_get_chroma_sub_sample(avctx->pix_fmt, &chroma_h_shift, &chroma_v_shift); if (avctx->codec->id == AV_CODEC_ID_LJPEG && avctx->pix_fmt == AV_PIX_FMT_BGR24) { vsample[0] = hsample[0] = vsample[1] = hsample[1] = vsample[2] = hsample[2] = 1; } else { vsample[0] = 2; vsample[1] = 2 >> chroma_v_shift; vsample[2] = 2 >> chroma_v_shift; hsample[0] = 2; hsample[1] = 2 >> chroma_h_shift; hsample[2] = 2 >> chroma_h_shift; } put_marker(pb, SOI); jpeg_put_comments(avctx, pb); jpeg_table_header(pb, intra_scantable, intra_matrix); switch (avctx->codec_id) { case AV_CODEC_ID_MJPEG: put_marker(pb, SOF0 ); break; case AV_CODEC_ID_LJPEG: put_marker(pb, SOF3 ); break; default: assert(0); } put_bits(pb, 16, 17); if (lossless && avctx->pix_fmt == AV_PIX_FMT_BGR24) put_bits(pb, 8, 9); /* 9 bits/component RCT */ else put_bits(pb, 8, 8); /* 8 bits/component */ put_bits(pb, 16, avctx->height); put_bits(pb, 16, avctx->width); put_bits(pb, 8, 3); /* 3 components */ /* Y component */ put_bits(pb, 8, 1); /* component number */ put_bits(pb, 4, hsample[0]); /* H factor */ put_bits(pb, 4, vsample[0]); /* V factor */ put_bits(pb, 8, 0); /* select matrix */ /* Cb component */ put_bits(pb, 8, 2); /* component number */ put_bits(pb, 4, hsample[1]); /* H factor */ put_bits(pb, 4, vsample[1]); /* V factor */ put_bits(pb, 8, 0); /* select matrix */ /* Cr component */ put_bits(pb, 8, 3); /* component number */ put_bits(pb, 4, hsample[2]); /* H factor */ put_bits(pb, 4, vsample[2]); /* V factor */ put_bits(pb, 8, 0); /* select matrix */ /* scan header */ put_marker(pb, SOS); put_bits(pb, 16, 12); /* length */ put_bits(pb, 8, 3); /* 3 components */ /* Y component */ put_bits(pb, 8, 1); /* index */ put_bits(pb, 4, 0); /* DC huffman table index */ put_bits(pb, 4, 0); /* AC huffman table index */ /* Cb component */ put_bits(pb, 8, 2); /* index */ put_bits(pb, 4, 1); /* DC huffman table index */ put_bits(pb, 4, lossless ? 0 : 1); /* AC huffman table index */ /* Cr component */ put_bits(pb, 8, 3); /* index */ put_bits(pb, 4, 1); /* DC huffman table index */ put_bits(pb, 4, lossless ? 0 : 1); /* AC huffman table index */ put_bits(pb, 8, lossless ? avctx->prediction_method + 1 : 0); /* Ss (not used) */ switch (avctx->codec_id) { case AV_CODEC_ID_MJPEG: put_bits(pb, 8, 63); break; /* Se (not used) */ case AV_CODEC_ID_LJPEG: put_bits(pb, 8, 0); break; /* not used */ default: assert(0); } put_bits(pb, 8, 0); /* Ah/Al (not used) */ }